Plasma processing device, power supply system, and control method

Abstract

A plasma processing device disclosed in the present invention comprises a chamber, a substrate support part, at least one RF power supply, a bias power supply, and a control circuit. The substrate support part is disposed in the chamber. The bias power supply supplies, to the substrate support part, a bias signal for attracting ions from plasma generated in the chamber to a substrate on the substrate support part. The control circuit changes the frequency of at least one RF signal over time so as to adjust the uniformity of a radial density distribution of the plasma during a period in which said at least one RF signal is supplied from said at least one RF power supply.

Description

Plasma Processing Apparatus, Power Supply System, and Control Method

[0001] An exemplary embodiment of the present disclosure relates to a plasma processing apparatus, a power supply system, and a control method.

[0002] The plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus uses bias high-frequency power to draw ions from the plasma generated in the chamber to the substrate. Patent Document 1 below discloses such a plasma processing apparatus.

[0003] Japanese Patent Application Laid-Open No. 2009-246091

[0004] The present disclosure provides a technique for adjusting the uniformity in the radial direction of plasma processing.

[0005] In one exemplary embodiment, a plasma processing apparatus is disclosed. The plasma processing apparatus includes a chamber, a substrate support, at least one RF power supply, a bias power supply, and a control circuit. The substrate support is disposed in the chamber. The bias power supply is configured to supply a bias signal to the substrate support for drawing ions from the plasma generated in the chamber to the substrate on the substrate support. The control circuit is configured to change the frequency of at least one RF signal over time so as to adjust the uniformity of the density distribution in the radial direction of the plasma during a period in which at least one RF signal is supplied from at least one RF power supply.

[0006] According to one exemplary embodiment, it is possible to adjust the uniformity in the radial direction of plasma processing.

[0007] This is a diagram illustrating an example configuration of a plasma processing system. This is a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus. This is a diagram showing an example of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a bias signal waveform. This is a diagram showing an example of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a substrate support part of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a substrate support part of a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of at least one sensor that can be used in a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a timing chart related to a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a table that can be used in a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a timing chart related to a plasma processing apparatus according to one exemplary embodiment. This is a diagram showing an example of a timing chart related to a plasma processing apparatus according to one exemplary embodiment. This is a flowchart showing a control method according to one exemplary embodiment. This is a block diagram of a computer (a type of circuit) capable of realizing the various control modes described herein.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] Figure 1 is a diagram illustrating an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 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] The following describes an example configuration of a capacitively coupled plasma processing apparatus as an example of a plasma processing apparatus 1. Figure 2 is a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus.

[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 rings are formed of a conductive or insulating material, and the covering rings are 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 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. If 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 lower frequency 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 100 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] 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.

[0026] Furthermore, the voltage level of the voltage pulse burst during the first period described above may change during the first period. For example, the voltage level of the voltage pulse burst during the first period may alternate between a first level and a second level during the first period. The first level is higher than the second level. The second level may be an OFF level (e.g., zero volts) or it may not be an OFF level.

[0027] Furthermore, the voltage level of the voltage pulse burst in the first period may have a first level for a portion of the first period and change to a second level and a third level for other periods of the first period. In this case, the first level is higher than the third level, unlike the second level, and the second level is higher than the third level. Also in this case, the voltage level of the voltage pulse burst in the first period may alternate between the second level and the third level for other periods of the first period.

[0028] The following references to Figures 3 and 4. Figures 3 and 4 are diagrams showing a plasma processing apparatus according to one exemplary embodiment. As shown in Figures 3 and 4, the plasma processing apparatus 1 includes a power supply system 50 used as a power supply system 30. The power supply system 50 includes at least one RF power supply (high-frequency power supply), a bias power supply 53, and a control circuit 50c. The power supply system 50 may include, as at least one RF power supply, a first RF power supply and / or a second RF power supply, i.e., an RF power supply 51 and / or an RF power supply 52.

[0029] The plasma processing apparatus 1 includes an upper conductor 18. The upper conductor 18 is positioned above the substrate support portion 11. The upper conductor 18 may be a single conductor. As shown in Figure 4, the upper conductor 18 may include an upper conductor 181 (first upper conductor) and an upper conductor 182 (second upper conductor). The upper conductor 181 is positioned above the substrate support portion 11. The upper conductor 182 is positioned radially outward of the upper conductor 181 and surrounds the upper conductor 181. The radial direction is radial with respect to the central axis of the chamber 10 or substrate support portion 11 that extends vertically.

[0030] The RF power supply 51 is electrically coupled to the upper conductor 18 or the substrate support 11 and is configured to generate a first RF signal (or source RF signal or source RF power), i.e., an RF signal RF1, in order to generate plasma from the gas in the chamber 10. The RF power supply 51 consists of a first RF generation unit 31a. The upper conductor 18 is the upper electrode 18u, which will be described later, when the plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus. The upper conductor 18 is the antenna 18a, which will be described later, when the plasma processing apparatus 1 is an inductively coupled plasma processing apparatus. The RF signal RF1 has a first frequency, i.e., frequency f1. When the plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus, the frequency f1 can be adjusted within the range of 4 MHz or more and 250 MHz or less. When the plasma processing apparatus 1 is an inductively coupled plasma processing apparatus, the frequency f1 can be adjusted within the range of 4 MHz or more and 60 MHz or less. The RF power supply 51 is electrically coupled to the upper conductor 18 or the substrate support 11 via a matching unit 51m. The variable impedance of the matching circuit 51m is set to reduce reflection of the RF signal RF1 from the load.

[0031] The RF power supply 52 is electrically coupled to the substrate support 11 (for example, the lower electrode) and is configured to generate a second RF signal, i.e., RF signal RF2, and supply RF signal RF2 to the substrate support 11. The RF power supply 52 consists of a second RF generation unit 31b or another RF generation unit. The RF signal RF2 has a second frequency, i.e., frequency f2. Frequency f2 is adjusted within the range of 4 MHz or more and 200 MHz or less. Frequency f2 may be lower than frequency f1. Frequency f2 is higher than the frequency f3 of the bias signal BS described later. The RF power supply 52 is electrically coupled to the substrate support 11 (for example, the lower electrode) via a matching unit 52m. The variable impedance of the matching unit 52m is set to reduce the reflection of RF signal RF2 from the load of the RF power supply 52.

[0032] Furthermore, the RF signal RF2 may be supplied to the substrate support 11 separately from the bias signal BS as a bias signal for drawing ions from the plasma in the chamber 10 to the substrate W on the substrate support 11. Also, if the plasma processing apparatus 1 does not include an RF power supply 51, the RF signal RF2 may be supplied to the substrate support 11 as a source RF signal for generating plasma from gas in the chamber 10.

[0033] The bias power supply 53 is electrically coupled to the substrate support portion 11 (for example, the lower electrode). The bias power supply 53 is configured to generate a bias signal BS for drawing ions from the plasma in the chamber 10 onto the substrate W on the substrate support portion 11.

[0034] Figure 5 shows an example of a bias signal waveform. As shown in Figure 5, the waveform of the bias signal BS has a waveform period Cb. The waveform period Cb is the shortest period of the waveform of the bias signal BS. The waveform period Cb has a time length that is the reciprocal of the third frequency, i.e., frequency f3. The frequency f3 can be between 50 kHz and 4 MHz.

[0035] The bias signal BS may be a bias RF signal having a frequency f3, as shown in the lower part of Figure 5. In this case, the bias signal BS is a high-frequency power (RF power) having a frequency f3 and has a sinusoidal waveform that is periodically generated with a waveform period Cb. In this case, the bias power supply 53 is composed of a second RF generation unit 31b or another RF generation unit. In this case, the bias power supply 53 is electrically coupled to the substrate support unit 11 via a matching unit 53m. The variable impedance of the matching unit 53m is set to reduce the reflection of the bias signal BS from the load of the bias power supply 53.

[0036] Alternatively, the bias signal BS may include voltage pulses VP that are generated periodically at time intervals equal to the time length of the waveform period Cb, as shown in the upper part of Figure 5. In this case, the bias power supply 53 is composed of a first voltage generation unit 32a and supplies a sequence of voltage pulses VP to the substrate support unit 11 as periodically generated voltage pulses VP. The waveform of each voltage pulse VP may be a square wave, a triangular wave, or any other waveform. The polarity of the voltage of the voltage pulse VP is set so that a potential difference is generated between the substrate W and the plasma, thereby attracting ions from the plasma to the substrate W. The voltage pulses VP are supplied to the substrate support unit 11 such that the waveform period Cb includes a period during which the potential of the substrate W is at a negative potential. Each voltage pulse VP may have a negative potential, a positive potential, or a potential that changes between a positive potential and a negative potential. The voltage pulse VP may be a pulse of negative voltage or a pulse of negative DC voltage. Furthermore, if the bias signal BS includes a voltage pulse VP, the plasma processing device 1 does not need to include a matching circuit 53m.

[0037] The control circuit 50c is configured to control at least one RF power supply, namely RF power supply 51 and / or RF power supply 52. ​​The control circuit 50c may also be configured to control bias power supply 53. The control circuit 50c may be part of any of RF power supply 51, RF power supply 52, and bias power supply 53. Alternatively, the control circuit 50c may be a separate circuit from RF power supply 51, RF power supply 52, and bias power supply 53. Details of the control circuit 50c will be described later.

[0038] As shown in Figures 3 and 4, the plasma processing apparatus 1 may include sensors 51s and 52s. Sensor 51s may include a directional coupler and may be configured to acquire the power level of the traveling wave and / or the power level of the reflected wave of the RF signal RF1 as its measured value. Sensor 51s may also include a voltage / current sensor and may be configured to measure the voltage and current of the RF signal RF1 in the power supply path of the RF signal RF1 and to acquire the impedance of the load from the measured voltage and current.

[0039] Sensor 52s may include a directional coupler and may be configured to acquire the power level of the forward wave and / or the power level of the reflected wave of the RF signal RF2 as its measured value. Sensor 52s may also include a voltage / current sensor and may be configured to measure the voltage and current of the RF signal RF2 in the power supply path of the RF signal RF2 and to acquire the load impedance from the measured voltage and current.

[0040] The plasma processing apparatus 1 may further include a sensor 53s. The sensor 53s measures the voltage and / or current of the bias signal BS in the power supply path for the bias signal BS that connects the bias power supply 53 and the substrate support portion 11 to each other. The control circuit 50c may determine the waveform period Cb of the bias signal BS from the voltage or current measured by the sensor 53s. The control circuit 50c may change the frequencies f1 and f2 as described later, with reference to the timing of the determined waveform period Cb.

[0041] The following is a reference to Figures 6 to 11. Figures 6 to 9 are diagrams showing examples of plasma processing apparatus according to one exemplary embodiment. Figures 10 and 11 are diagrams showing examples of substrate support parts of plasma processing apparatus according to one exemplary embodiment.

[0042] As shown in Figures 6 and 7, the plasma processing apparatus 1 may be a capacitively coupled plasma processing apparatus and may include an upper electrode 18u as the upper conductor 18. As shown in Figure 6, the upper electrode 18u may be a single upper electrode in a capacitively coupled plasma processing apparatus. In this case, the RF power supply 51 may supply an RF signal RF1 to the upper electrode 18u.

[0043] Alternatively, as shown in FIG. 7, the upper electrode 18u may include an upper conductor 181u as the upper conductor 181 and an upper conductor 182u as the upper conductor 182. The upper conductor 181u extends above the central region of the substrate support portion 11. The upper conductor 182u surrounds the upper conductor 181u. The upper conductor 182u may extend above the edge region of the substrate support portion 11. The upper conductor 182u is electrically separated from the upper conductor 181u. The RF signal RF1 is distributed to the upper conductor 181u and the upper conductor 182u. In this case, the electrical path extending from the output of the RF power supply 51 is branched into a first path connected to the upper conductor 181u and a second path connected to the upper conductor 182u. At least one of the first path and the second path may include a variable capacitor. In the example of FIG. 7, the first path includes the variable capacitor 191. The capacitance of the variable capacitor 191 can be adjusted by the control circuit 50c. By the variable capacitor 191, the distribution ratio of the RF signal RF1 to each of the upper conductor 181u and the upper conductor 182u can be adjusted.

[0044] As shown in FIG. 8, the plasma processing apparatus 1 may be an inductively coupled plasma processing apparatus, and may include an antenna 18a as the upper conductor 18. When the plasma processing apparatus 1 is an inductively coupled plasma processing apparatus, the top portion of the chamber 10 includes a dielectric window 15. The antenna 18a is provided on the dielectric window 15. The antenna 18a includes at least one coil.

[0045] In the example shown in Figure 8, the antenna 18a includes a coil 181c as an upper conductor 181 and a coil 182c as an upper conductor 182. Each of the coils 181c and 182c extends in a spiral shape. Each of the coils 181c and 182c may extend around the central axis of the chamber 10. Coil 181c is located inside coil 182c. The RF signal RF1 is distributed to coils 181c and 182c. In this case, the electrical path extending from the output of the RF power supply 51 is branched into a first path connected to coil 181c and a second path connected to coil 182c. At least one of the first and second paths may include a variable capacitor. In the example shown in Figure 8, the first path includes a variable capacitor 191 and the second path includes a variable capacitor 192. The capacitances of the variable capacitors 191 and 192 can be adjusted by the control circuit 50c. The variable capacitors 191 and 192 allow adjustment of the distribution ratio of the RF signal RF1 to coils 181c and 182c, respectively.

[0046] In the example shown in Figure 8, the gas introduction section of the plasma processing apparatus 1 includes a central gas injection section (CGI) 13B. The central gas injection section 13B is positioned above the substrate support section 11 and is attached to a central opening formed in the dielectric window 15. The central gas injection section 13B has at least one gas supply port 13Ba, at least one gas flow path 13Bb, and at least one gas inlet 13Bc. The processing gas supplied from the gas supply section 20 to the gas supply port 13Ba passes through the gas flow path 13Bb and is introduced into the plasma processing space 10s from the gas inlet 13Bc. In addition to or instead of the central gas injection section 13B, the gas introduction section may also include one or more side gas injection sections (SGIs) attached to one or more openings formed in the side wall of the chamber 10.

[0047] In the example shown in FIG. 9 as well, the plasma processing apparatus 1 is an inductively coupled plasma processing apparatus. In FIG. 9, the illustration of the central gas injection portion 13B is omitted. In the example of FIG. 9, the electrical path extending from the RF power supply 51 is connected to the coil 182c and not to the coil 181c. A variable capacitor 193 is connected between both ends of the coil 181c. The capacitance of the variable capacitor 193 can be adjusted by the control circuit 50c. By adjusting the capacitance of the variable capacitor 193 to adjust the resonance state between the coil 181c and the coil 182c, the RF signal RF1 is also supplied to the coil 181c.

[0048] In various exemplary embodiments, the plasma processing apparatus 1 may include the substrate support portion 11 shown in FIG. 10 or FIG. 11. In the example shown in FIG. 10, the substrate support portion 11 further has an electrode 1111d inside the electrostatic chuck 1111. The electrode 1111d is disposed below the above-described ring support surface within the ceramic member 1111a. The electrode 1111d is a conductive film formed of a metal material and extends in the horizontal and circumferential directions. The electrode 1111d may have a ring shape. In this example, the bias power supply 53 is electrically connected to the base 1110 and is configured to supply a bias signal BS to the base 1110. The RF power supply 52 is electrically connected to the base 1110 and the electrode 1111d and is configured to supply an RF signal RF2 to the base 1110 and the electrode 1111d. The electrical path extending from the RF power supply 52 branches into a first path connected to the base 1110 and a second path connected to the electrode 1111d. At least one of the first path and the second path may include a variable capacitor. In the example of FIG. 10, the first path includes the variable capacitor 194. The capacitance of the variable capacitor 194 can be adjusted by the control circuit 50c. By the variable capacitor 194, the distribution ratio of the RF signal RF2 to the base 1110 and the electrode 1111d respectively can be adjusted.

[0049] The substrate support portion 11 in the example of Figure 11 differs from the substrate support portion 11 in the example of Figure 10 in that it further includes an electrode 1111c. The electrode 1111c is located within the ceramic member 1111a below the substrate support surface and / or electrostatic chuck electrode 1111b. The electrode 1111c is a conductive film formed from a metallic material and extends horizontally. The electrode 1111c may have a circular shape. The electrode 1111d surrounds the electrode 1111c. In this example, the bias power supply 53 is electrically connected to the base 1110 and is configured to supply a bias signal BS to the base 1110. The RF power supply 52 is electrically connected to the electrodes 1111c and 1111d and is configured to supply an RF signal RF2 to the electrodes 1111c and 1111d. In this example, the electrical path extending from the RF power supply 52 is branched into a first path connected to electrode 1111c and a second path connected to electrode 1111d. At least one of the first and second paths may include a variable capacitor. In the example in Figure 11, the first path includes a variable capacitor 194. The capacitance of the variable capacitor 194 can be adjusted by the control circuit 50c. The variable capacitor 194 can adjust the distribution ratio of the RF signal RF2 to electrodes 1111c and 1111d.

[0050] Refer to Figure 12 below. This figure shows an example of at least one sensor that can be used in a plasma processing apparatus according to one exemplary embodiment. In various exemplary embodiments, the plasma processing apparatus 1 may further include at least one sensor. The at least one sensor is configured to acquire at least one measurement that reflects the radial density distribution of the plasma in the chamber 10. In the example of Figure 12, the plasma processing apparatus 1 includes sensor 61 (first sensor) and sensor 62 (second sensor).

[0051] Sensor 61 may acquire a measurement value (first measurement value) in a first portion at the radial center of the plasma processing space 10s. Sensor 62 may acquire a measurement value (second measurement value) in a second portion at the radial outer edge of the plasma processing space 10s (for example, the portion above the edge of the substrate W). The measurement values ​​acquired by sensors 61 and 62, respectively, may be the plasma density or the plasma emission intensity.

[0052] Alternatively, sensor 61 may acquire the magnitude of the voltage or current in the upper conductor 181 as a measured value. Sensor 62 may acquire the magnitude of the voltage or current in the upper conductor 182 as a measured value.

[0053] Furthermore, at least one sensor may include a sensor that acquires the peak-to-peak voltage, i.e., voltage Vpp, in a conductor section to which at least one RF signal is supplied. The conductor section may be at least one of the upper conductor 18, upper conductor 181, upper conductor 182, base 1110, electrode 1111c, and electrode 1111d. Also, at least one sensor may include a sensor that acquires the pressure in the plasma processing space 10s.

[0054] The following refers to Figures 13 and 14. Figures 13 and 14 are diagrams showing examples of timing charts related to a plasma processing apparatus according to one exemplary embodiment. In Figures 13 and 14, "ON" for RF signal RF1 indicates that RF signal RF1 is being supplied. "OFF" for RF signal RF1 indicates that the supply of RF signal RF1 has been stopped. "ON" for RF signal RF2 indicates that RF signal RF2 is being supplied to the substrate support 11. "OFF" for RF signal RF2 indicates that the supply of RF signal RF2 to the substrate support 11 has been stopped. Also, "ON" for bias signal BS indicates that bias signal BS is being supplied to the substrate support 11. "OFF" for bias signal BS indicates that the supply of bias signal BS to the substrate support 11 has been stopped.

[0055] As shown in Figure 13, RF power supplies 51, RF power supplies 52, and bias power supplies 53 may each periodically supply pulses of RF signal RF1, RF signal RF2, and bias signal BS in synchronization. The pulses of RF signal RF1, RF signal RF2, and bias signal BS are supplied periodically at time intervals of pulse period Cp. Each of the pulses of RF signal RF1, RF signal RF2, and bias signal BS is a pulse that includes a period in which the signal is ON and a period in which the signal is OFF. Each of the pulses of RF signal RF1, RF signal RF2, and bias signal BS may be a HIGH / LOW pulse that includes a period in which the signal level is high and a period in which the signal level is low.

[0056] The control circuit 50c is configured to change the frequency of at least one RF signal over time to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma during a period Pc in which at least one RF signal is supplied. In the example in Figure 13, the period Pc is the ON state during each pulse period Cp or within each pulse period Cp during which the pulses of RF signal RF1, RF signal RF2, and bias signal BS are each sustained. In the example in Figure 13, the control circuit 50c changes the frequencies f1 and f2 over time within each pulse period Cp to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma.

[0057] In the example in Figure 14, the period Pc is each waveform period Cb. In the example in Figure 14, the control circuit 50c changes the frequencies f1 and f2 over time to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma within each waveform period Cb.

[0058] The control circuit 50c may refer to a pre-prepared table for setting frequencies f1 and f2 within the period Pc. The table may be stored in a memory unit of the control circuit 50c.

[0059] Figure 15 shows an example of a table that can be used in a plasma processing apparatus according to one exemplary embodiment. The table has identifiers for each of the multiple processes, i.e., multiple process IDs, registered as keys. The table has multiple frequency sets for frequency f1 and / or multiple frequency sets for frequency f2, each associated with the multiple process IDs. Each frequency set for frequency f1 contains multiple (N) frequencies that are used sequentially as frequency f1 over time within a period Pc, i.e., frequencies f1[1], ..., f1[N]. Each frequency set for frequency f2 contains multiple (N) frequencies that are used sequentially as frequency f2 over time within a period Pc, i.e., frequencies f2[1], ..., f2[N]. Multiple frequency sets for frequency f1 and multiple frequency sets for frequency f2 for each process can be prepared by performing each process using different frequency sets for frequency f1 and different frequency sets for frequency f2, and selecting the frequency sets for frequency f1 and frequency f2 that yield the highest radial uniformity of the plasma treatment on the substrate.

[0060] The control circuit 50c acquires a frequency set for frequency f1 and a frequency set for frequency f2 corresponding to the process ID specified by the control unit 2. The control circuit 50c may set the frequency f1 within the period Pc to the frequencies f1[1], ..., f1[N] included in the acquired frequency set in order. The control circuit 50c may also set the frequency f2 within the period Pc to the frequencies f2[1], ..., f2[N] included in the acquired frequency set in order.

[0061] In one embodiment, the control circuit 50c may change the frequencies f1 and / or f2 over time within the period Pc to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma, according to the measured values ​​of sensor 61 and sensor 62, or the ratio of the measured values ​​of sensor 61 and sensor 62. In this case, the frequency sets for frequency f1 and / or frequency sets for frequency f2 in the above table may or may not be used as the initial series of frequencies f1 and frequency f2 within the period Pc.

[0062] In one embodiment, the control circuit 50c predicts the radial density distribution of the plasma in the chamber 10 from at least one of the following: the plasma impedance acquired by sensor 51s and / or sensor 52s, the voltage Vpp, the position of matcher 51m and / or matcher 52m, the power level of the traveling or reflected wave of RF signal RF1 and / or the power level of the traveling or reflected wave of RF signal RF2, and the pressure in the chamber 10. The control circuit may change frequencies f1 and / or f2 over time within the period Pc to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma according to the predicted radial density distribution of the plasma. The positions of matcher 51m and matcher 52m are parameters that reflect the impedance in matcher 51m and the impedance in matcher 52m, respectively.

[0063] The following references to Figures 16 and 17. Figures 16 and 17 are examples of timing charts related to a plasma processing apparatus according to one exemplary embodiment. As shown in Figure 16, the control circuit 50c may change the power level of the RF signal RF1 over time within a period Pc (in the example of Figure 16, each waveform period Cb). The power level of the RF signal RF1 within a period Pc may be changed to reduce the time variation of the average plasma density in the chamber 10. In the example of Figure 16, the power level of the RF signal RF2 is constant within a period Pc (in the example of Figure 16, each waveform period Cb), but the RF signal RF2 may not be supplied.

[0064] As shown in Figure 17, the control circuit 50c may change the power levels of RF signal RF1 and RF signal RF2 over time within a period Pc (in the example in Figure 17, each waveform period Cb). The power levels of RF signal RF1 and RF signal RF2 within a period Pc may be changed to reduce the time variation of the average plasma density in the chamber 10.

[0065] In the plasma processing apparatus 1, the frequencies f1 and / or f2 are changed within a period Pc to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma. Therefore, the plasma processing apparatus 1 can adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma by suppressing the temporal changes in the radial density distribution of the plasma that would occur if the frequencies f1 and / or f2 were not changed. Thus, the plasma processing apparatus 1 can improve the radial uniformity of the plasma processing (e.g., plasma etching) of the substrate W.

[0066] A control method according to one exemplary embodiment will be described below with reference to Figure 18. Figure 18 is a flowchart showing a control method according to one exemplary embodiment. The control method shown in Figure 18 (hereinafter referred to as "Method MT") can be performed using the plasma processing apparatus 1. In each step of Method MT, each part of the plasma processing apparatus 1 can be controlled by the control unit 2 and / or the control circuit 50c.

[0067] Method MT includes steps STa to STc. In step STa, at least one RF signal, for example, RF signal RF1 from RF power supply 51 and / or RF signal RF2 from RF power supply 52, is supplied to the substrate W for plasma processing. Step STb may be performed together with step STa. In step STb, a bias signal BS from bias power supply 53 is supplied to the substrate support 11.

[0068] Process STc is performed during a period Pc (e.g., each waveform period Cb or each pulse period Cp) in which at least one RF signal, for example RF signal RF1 and / or RF signal RF2, is supplied. During process STc, the frequency of at least one RF signal (e.g., frequency f1 and / or frequency f2) is changed over time to adjust or control (e.g., improve) the uniformity of the radial density distribution of the plasma during period Pc. For details of the changes in the frequency of at least one RF signal in process STc, please refer to the above description of the plasma processing apparatus 1.

[0069] The following describes examples of circuits (control circuits) that may constitute the control unit 2 and / or control circuit 50c.

[0070] Figure 19 illustrates a block diagram of a computer (a type of circuit) capable of implementing the various control modes described herein. Furthermore, the control modes of this disclosure can be implemented as a system, method, and / or computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions causing one or more processing units to execute the modes of this embodiment are recorded.

[0071] A computer-readable storage medium may be a tangible device capable of storing instructions used by an instruction execution device (processor). A computer-readable storage medium may, but is not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples of computer-readable storage media include, but are not exhaustive, flexible disks, hard disks, solid-state drives (SSDs), random-access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash), static random-access memory (SRAM), compact disks (CDs or CD-ROMs), digital multipurpose disks (DVDs), memory cards or memory sticks (and suitable combinations thereof). In this disclosure, a computer-readable storage medium should not be interpreted as, for example, a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse passing through an optical fiber cable), or a transient signal itself, such as an electrical signal transmitted through a wire.

[0072] The computer-readable program instructions described in this disclosure can be downloaded from a computer-readable storage medium to a suitable computing device or processing device, or they can be downloaded to an external computer or external storage device via a global network (i.e., the Internet), a local area network, a wide area network, and / or a wireless network. Networks include transmission copper wires, optical fiber, wireless communications, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface of each computing device or processing device can receive computer-readable program instructions from the network, transfer those computer-readable program instructions, and store them in a computer-readable storage medium within the computing device or processing device.

[0073] Computer-readable program instructions for performing the operations of the Disclosure may include machine language instructions and / or microcode. These instructions can be compiled or interpreted from source code written in any combination of one or more programming languages, including assembly language, Basic, Fortran, Java®, Python, R, C, C++, C#, etc. Computer-readable program instructions can be fully executed on a user's personal computer, notebook computer, tablet, or smartphone, or may be fully executed on a remote computer or computer server, or on any combination of these computing devices. The remote computer or computer server may be connected to one or more of the user's devices via a computer network, including a local area network, a wide area network, or a global network (i.e., the Internet). Alternatively, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), may be configured or customized to execute computer-readable program instructions using information from the computer-readable program instructions and implement embodiments of the Disclosure.

[0074] This specification will describe aspects of the present disclosure with reference to flowcharts and block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. Those skilled in the art will understand that each block in the flowcharts and block diagrams, as well as combinations of blocks in the flowcharts and block diagrams, can be implemented by computer-readable program instructions.

[0075] Computer-readable program instructions capable of implementing the systems and methods described in this disclosure may be supplied to one or more processors (and / or one or more cores within a processor) of a general-purpose computer, a dedicated computer, or other programmable device. This makes it possible to generate a machine that constructs a system for implementing the functions specifically shown in the flowcharts and block diagrams of this disclosure, through instructions executed via the processors of the computer or other programmable device. These computer-readable program instructions may also be stored in a computer-readable storage medium that can instruct the computer, programmable device, and / or other device to function in a particular manner. The computer-readable storage medium storing the instructions is a product containing instructions that implement the embodiments of the functions specifically shown in the flowcharts and block diagrams of this disclosure.

[0076] Furthermore, computer-readable program instructions can be loaded into a computer, another programmable device, or other device, and a series of operations can be executed on that computer, other programmable device, or other device to realize a computer implementation process. Therefore, the functions specifically shown in the flowcharts and block diagrams of this disclosure can be realized by instructions executed on a computer, another programmable device, or other device.

[0077] Figure 19 is a functional block diagram showing a network system 800 in which one or more computers and servers are connected to a network. In one embodiment, the hardware and software environments illustrated in Figure 19 may serve as an exemplary platform for implementing the software and / or methods relating to this disclosure.

[0078] Referring to Figure 19, the network system 800 may include, but is not limited to, a computer 805, a network 810, a remote computer 815, a web server 820, a cloud storage server 825, and a computer server 830. In some embodiments, one or more examples of the functional blocks illustrated in Figure 19 may be used.

[0079] Further details of computer 805 are shown in Figure 19. The functional blocks illustrated within computer 805 are merely illustrative examples for constructing exemplary functions and do not encompass all of its capabilities. Details of the remote computer 815, web server 820, cloud storage server 825, and computer server 830 are not shown, but these computers and devices may also include functions similar to those shown for computer 805.

[0080] Computer 805 may be a personal computer (PC), desktop computer, laptop computer, tablet computer, netbook computer, personal data device (PDA), smartphone, or other programmable electronic device capable of communicating with other devices on the network 810.

[0081] The computer 805 may include a processing unit 835, a bus 837, a memory 840, a non-volatile storage device 845, a network interface 850, a peripheral device interface 855, and a display device interface 865. In some embodiments, these functions may be implemented as individual electronic subsystems (integrated circuit chips or combinations of chips and associated devices), while in other embodiments, some of the combinations of functions may be implemented on a single chip (also known as a system-on-a-chip or SoC).

[0082] The processing unit 835 may be one or more single-chip or multi-chip microprocessors designed and / or manufactured by Intel Corporation, Advanced Micro Devices, Inc. (AMD), Arm Holdings, Apple Computer, etc. Examples of microprocessors include Intel Corporation's Celeron, Pentium®, Core i3, Core i5, Core i7; AMD's Opteron, Phenom, Athlon, Turion, Ryzen; and Arm's Cortex-A, Cortex-R, Cortex-M, etc.

[0083] Bus 837 may be a proprietary or industry-standard high-speed parallel or serial peripheral interconnect bus such as ISA, PCI, PCI Express (PCI-e), or AGP.

[0084] The memory 840 and the non-volatile storage device 845 may be computer-readable storage media. The memory 840 may include any suitable volatile storage device such as dynamic random access memory (DRAM) and static random access memory (SRAM). The non-volatile storage device 845 may include one or more of the following: flexible disk, hard disk, solid-state drive (SSD), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash), compact disc (CD or CD-ROM), digital multipurpose disc (DVD), memory card, or memory stick.

[0085] The program 848 may be a collection of machine-readable instructions and / or machine-readable data stored in at least one memory, such as a non-volatile storage device 845, and used to create, manage, and control specific software functions as described in detail and illustrated in the drawings of this disclosure. In some embodiments, memory 840 may be much faster than the non-volatile storage device 845. In that case, the program 848 may be transferred from the non-volatile storage device 845 to memory 840 and then executed by the processing unit 835. The program 848 includes computer program code. In one implementation, at least one memory storing the computer program code comprises at least one processing unit (such as a processing circuit described later) for carrying out the control process and claimed advanced embodiments of this disclosure.

[0086] Computer 805 may communicate and interact with other computers via network 810 using network interface 850. Network 810 may be, for example, a local area network (LAN), a wide area network (WAN) such as the Internet, or a combination thereof, and may include wired, wireless, or fiber optic connections. In general, network 810 can be any combination of connections and protocols that support communication between two or more computers and associated devices.

[0087] The peripheral interface 855 may enable data input and output via other devices that can be locally connected to the computer 805. For example, the peripheral interface 855 may enable connection to an external device 860. The external device 860 may include devices such as a keyboard, mouse, keypad, touchscreen, and / or other suitable input devices. The external device 860 may also include portable computer-readable storage media such as a thumb drive, portable optical or magnetic disk, and memory card. Software and data used to implement embodiments of the present disclosure (e.g., program 848) may be stored on such portable computer-readable storage media. In this case, the software may be loaded into the non-volatile storage device 845, or directly into memory 840 via the peripheral interface 855. The peripheral interface 855 may use industry-standard connections such as RS-232 or Universal Serial Bus (USB) to connect to the external device 860.

[0088] The computer 805 may be connected to the display device 870 via the display device interface 865. In one embodiment, the display device 870 may be used to present a command line or a graphical user interface to the user of the computer 805. The display device interface 865 may be connected to the display device 870 using one or more proprietary or industry standard connections such as VGA, DVI, DisplayPort, HDMI®, etc.

[0089] As described above, the network interface 850 enables communication with other computing systems or storage systems or computing devices or storage devices outside of the computer 805. The software programs and data described herein may be downloaded to the non-volatile storage device 845 via the network interface 850 and network 810 from, for example, a remote computer 815, a web server 820, a cloud storage server 825, or a computer server 830. Furthermore, the systems and methods described herein may be implemented by one or more computers connected to the computer 805 via the network interface 850 and network 810. For example, in one embodiment, the systems and methods described herein may be implemented by a combination of a remote computer 815, a computer server 830, or computers interconnected on network 810.

[0090] The data, datasets, and / or databases used in the embodiments of the systems and methods described herein may be stored in or downloaded from a remote computer 815, a web server 820, a cloud storage server 825, or a computer server 830.

[0091] The circuits used in this application can be defined as one or more of the following: electronic components (such as semiconductor devices), a plurality of electronic components directly connected to each other or interconnected via electronic communication, a computer, a network of computer devices, a remote computer, a web server, a cloud storage server, or a computer server. For example, each of the one or more of the computer, remote computer, web server, cloud storage server, and computer server may be included as a component of the circuit, or may include the circuit. In some embodiments, one or more examples of these components may be used, and each of the one or more examples of these components may also be included in the circuit, or may include the circuit. In some embodiments, a circuit represented by a network system may include a serverless computing system that corresponds to virtualized hardware resources. A circuit represented by a computer may be a personal computer (PC), a desktop computer, a laptop computer, a tablet computer, a netbook computer, a personal data device (PDA), a smartphone, or other programmable electronic device that can communicate with other devices on a network. The circuit may be a general-purpose computer, a dedicated computer, or other programmable device described herein that includes one or more processing units. Each processing unit may be one or more single-chip microprocessors or multi-chip microprocessors. One or more processing units are considered processing circuits or circuits because they incorporate transistors and other circuits. The circuits can implement the systems and methods described in this disclosure based on computer-readable program instructions. These program instructions are supplied to one or more processing units (and / or one or more cores within processing units) of one or more general-purpose computers, dedicated computers, or other programmable devices described herein. This makes it possible to generate a machine that constructs a system for implementing the functions specifically shown in the flowcharts and block diagrams of this disclosure, through instructions contained within the circuits or executed via one or more processing units of a programmable device containing the circuits.Alternatively, a circuit may be a pre-programmed structure, such as a programmable logic device or an application-specific integrated circuit. A circuit is considered a circuit whether it is used alone or in combination with other programmable circuits or other pre-programmed circuits.

[0092] In light of the above teachings, it is clear that numerous modifications and variations of the present invention are possible. Therefore, it should be understood that, within the scope of the appended claims, the present invention can be implemented in forms other than those specifically described herein.

[0093] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0094] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E14] below.

[0095] [E1] A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; at least one RF power supply; a bias power supply configured to supply a bias signal to the substrate support for drawing ions from the plasma generated in the chamber onto a substrate on the substrate support; and a control circuit, wherein the control circuit is configured to change the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which at least one RF signal is supplied from the at least one RF power supply.

[0096] [E2] The plasma processing apparatus according to E1, wherein the at least one RF power supply is configured to periodically supply pulses of the at least one RF signal, and the period is the duration of the pulses.

[0097] [E3] The plasma processing apparatus according to E1, wherein the bias signal has a waveform period and is supplied periodically at time intervals of the waveform period, and the period is the waveform period of the bias signal.

[0098] [E4] The plasma processing apparatus according to any one of E1 to E3, wherein the control circuit includes a storage unit having a table containing a plurality of identifiers that each identify a plurality of processes, and a plurality of frequency sets that are prepared in advance and each associated with the plurality of identifiers, and is configured to obtain from the storage unit a frequency set associated with the identifier of a specified process from among the plurality of frequency sets, and to change the frequency of the at least one RF signal over the period of time by sequentially using the plurality of frequencies in the obtained frequency set.

[0099] [E5] The plasma processing apparatus according to any one of E1 to E4, further comprising at least one sensor configured to acquire at least one measurement value that reflects the radial density distribution of plasma in the chamber, wherein the control circuit is configured to change the frequency of the at least one RF signal over the period of time in accordance with the at least one measurement value acquired by the at least one sensor.

[0100] [E6] The plasma processing apparatus according to E5, wherein the at least one sensor includes a first sensor and a second sensor, and each of the first sensor and the second sensor is configured to obtain, as at least one measurement value, a first measurement value which is the density or luminescence intensity of the plasma in a first portion radially central to the plasma, and a second measurement value which is the density or luminescence intensity of the plasma in a second portion radially outside the first portion.

[0101] [E7] The plasma processing apparatus is a capacitively coupled plasma processing apparatus including an upper electrode comprising a first upper conductor extending above the substrate support portion and a second upper conductor positioned radially outward from the first upper conductor and surrounding the first upper conductor, or an inductively coupled plasma processing apparatus having an antenna comprising a first upper conductor which is a coil extending above the substrate support portion and a second upper conductor which is a coil that surrounds the first upper conductor radially outward from the first upper conductor, wherein the at least one sensor comprises a first sensor and a second sensor, and the first sensor and the second sensor are configured to acquire, as at least one measured value, a first measured value which is the magnitude of the current or voltage in the first upper conductor and a second measured value which is the magnitude of the current or voltage in the second upper conductor.

[0102] [E8] The plasma processing apparatus according to E6 or E7, wherein the control circuit is configured to change the frequency of the at least one RF signal over the period of time according to the ratio of the first measured value to the second measured value.

[0103] [E9] The plasma apparatus according to any one of E1 to E4, further comprising at least one sensor configured to acquire a measurement of at least one of the following: the impedance of the plasma in the chamber, the peak-to-peak voltage in a conductor of the plasma apparatus supplied with the at least one RF signal, the position of a matching circuit connected between the at least one RF power supply and a load, the power level of the at least one RF signal, and the pressure in the chamber, wherein the control circuit is configured to predict the radial density distribution of the plasma from the at least one measurement acquired by the at least one sensor, and to change the frequency of the at least one RF signal over the period of time according to the predicted radial density distribution of the plasma.

[0104] [E10] The plasma processing apparatus according to any one of E1 to E9, wherein the at least one RF power supply comprises: a first RF power supply configured to generate a first RF signal for generating plasma from a gas in a chamber; and a second RF power supply configured to supply a second RF signal having a frequency lower than the frequency of the first RF signal and higher than the frequency of the bias signal, wherein the at least one RF signal comprises the first RF signal and / or the second RF signal.

[0105] [E11] The plasma processing apparatus according to E10, wherein the first RF power supply is electrically connected to an upper conductor which is an antenna or upper electrode provided above the substrate support portion.

[0106] [E12] The plasma processing apparatus according to any one of E1 to E11, wherein the control circuit is configured to change the power level of at least one RF signal over time in order to reduce the temporal change in the average density of the plasma in the chamber.

[0107] [E13] A power supply system comprising: at least one RF power supply; a bias power supply configured to supply a bias signal to a substrate support for drawing ions from plasma generated in the chamber of a plasma processing apparatus to a substrate on a substrate support within the chamber; and a control circuit, wherein the control circuit is configured to change the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which at least one RF signal is supplied from the at least one RF power supply.

[0108] [E14] A control method comprising: (a) supplying at least one RF signal; (b) supplying a bias signal to a substrate support for drawing ions from the plasma generated in the chamber of the plasma processing apparatus to a substrate on a substrate support within the chamber; and (c) changing the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which the at least one RF signal is supplied.

[0109] From the above description, it will be understood that the various embodiments of this disclosure are described herein for illustrative purposes and can be modified in various ways without departing from the scope and spirit of this disclosure. Accordingly, the various embodiments disclosed herein are not intended to limit the scope and spirit, and the true scope and spirit are shown by the appended claims.

[0110] 1...Plasma processing apparatus, 10...Chamber, 11...Substrate support section, 18...Upper conductor, 50...Power supply system, 51...RF power supply, 52...RF power supply, 53...Bias power supply, 50c...Control circuit.

Claims

1. A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; at least one RF power supply; a bias power supply configured to supply a bias signal to the substrate support for drawing ions from the plasma generated in the chamber to a substrate on the substrate support; and a control circuit, wherein the control circuit is configured to change the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which at least one RF signal is supplied from the at least one RF power supply.

2. The plasma processing apparatus according to claim 1, wherein the at least one RF power supply is configured to periodically supply pulses of the at least one RF signal, and the period is the duration of the pulses.

3. The plasma processing apparatus according to claim 1, wherein the bias signal has a waveform period and is supplied periodically at time intervals of the waveform period, and the period is the waveform period of the bias signal.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein the control circuit includes a storage unit having a table containing a plurality of identifiers that each specify a plurality of processes, and a plurality of pre-prepared frequency sets, each of which is associated with the plurality of identifiers, and is configured to retrieve from the storage unit a frequency set associated with the identifier of a specified process from among the plurality of frequency sets, and to change the frequency of the at least one RF signal over the period of time by sequentially using the plurality of frequencies in the retrieved frequency set.

5. The plasma processing apparatus according to any one of claims 1 to 3, further comprising at least one sensor configured to acquire at least one measurement value that reflects the radial density distribution of plasma in the chamber, wherein the control circuit is configured to change the frequency of the at least one RF signal over the period of time in accordance with the at least one measurement value acquired by the at least one sensor.

6. The plasma processing apparatus according to claim 5, wherein the at least one sensor includes a first sensor and a second sensor, and each of the first sensor and the second sensor is configured to obtain, as at least one measurement value, a first measurement value which is the density or luminescence intensity of the plasma in a first portion radially central to the plasma, and a second measurement value which is the density or luminescence intensity of the plasma in a second portion radially outside the first portion.

7. The plasma processing apparatus is a capacitively coupled plasma processing apparatus including an upper electrode comprising a first upper conductor extending above the substrate support portion and a second upper conductor positioned radially outward from the first upper conductor and surrounding the first upper conductor, or an inductively coupled plasma processing apparatus having an antenna comprising a first upper conductor which is a coil extending above the substrate support portion and a second upper conductor which is a coil that surrounds the first upper conductor radially outward from the first upper conductor, wherein the at least one sensor comprises a first sensor and a second sensor, and the first sensor and the second sensor are configured to acquire, as at least one measured value, a first measured value which is the magnitude of the current or voltage in the first upper conductor and a second measured value which is the magnitude of the current or voltage in the second upper conductor.

8. The plasma processing apparatus according to claim 6, wherein the control circuit is configured to change the frequency of the at least one RF signal over the period of time according to the ratio of the first measured value to the second measured value.

9. The plasma apparatus according to any one of claims 1 to 3, further comprising at least one sensor configured to acquire a measurement of at least one of the following: the impedance of the plasma in the chamber, the peak-to-peak voltage in a conductor of the plasma apparatus supplied with the at least one RF signal, the position of a matching circuit connected between the at least one RF power supply and a load, the power level of the at least one RF signal, and the pressure in the chamber, wherein the control circuit is configured to predict the radial density distribution of the plasma from the at least one measurement acquired by the at least one sensor, and to change the frequency of the at least one RF signal over the period of time according to the predicted radial density distribution of the plasma.

10. The plasma processing apparatus according to any one of claims 1 to 3, wherein the at least one RF power supply includes: a first RF power supply configured to generate a first RF signal for generating plasma from a gas in a chamber; and a second RF power supply configured to supply a second RF signal having a frequency lower than the frequency of the first RF signal and higher than the frequency of the bias signal, the at least one RF signal including the first RF signal and / or the second RF signal.

11. The plasma processing apparatus according to claim 10, wherein the first RF power supply is electrically connected to an upper conductor which is an antenna or upper electrode provided above the substrate support portion.

12. The plasma processing apparatus according to any one of claims 1 to 3, wherein the control circuit is configured to change the power level of at least one RF signal over time in order to reduce the temporal variation in the average density of the plasma in the chamber.

13. A power supply system comprising: at least one RF power supply; a bias power supply configured to supply a bias signal to a substrate support for drawing ions from plasma generated in the chamber of a plasma processing apparatus to a substrate on a substrate support within the chamber; and a control circuit, wherein the control circuit is configured to change the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which at least one RF signal is supplied from the at least one RF power supply.

14. A control method comprising: (a) supplying at least one RF signal; (b) supplying a bias signal to a substrate support for drawing ions from the plasma generated in the chamber of the plasma processing apparatus to a substrate on a substrate support within the chamber; and (c) changing the frequency of the at least one RF signal over time to adjust the uniformity of the radial density distribution of the plasma during the period in which the at least one RF signal is supplied.

Images