Plasma processing apparatus, power supply system, control method, program, and storage medium

Abstract

In this plasma treatment device, electric bias energy is supplied from a bias power source to a substrate support part. Source high-frequency power is supplied from a high-frequency power source to a high-frequency electrode. The high-frequency power source selects, from among a plurality of frequency sets, an initial frequency set obtained according to a designated process. The high-frequency power source uses, as a plurality of source frequencies of the source high-frequency power, respectively, for a plurality of phase periods within the waveform period of the electric bias energy, a plurality of frequencies included in the initial frequency set in a first period. The high frequency power source adjusts the plurality of source frequencies of the source high-frequency power, respectively, for the plurality of phase periods within the waveform period of the electric bias energy in a second period.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing apparatus, a power supply system, a control method, a program, and a storage medium.

Background Art

[0002] A plasma processing apparatus is used in plasma processing of a substrate. In the plasma processing apparatus, bias high-frequency power is used to draw ions from the plasma generated in the chamber to the substrate. The following Patent Document 1 discloses a plasma processing apparatus that modulates the power level and frequency of the bias high-frequency power.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for reducing the power level of the reflected wave of the source high-frequency power.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a bias power supply, and a high-frequency power supply. The substrate support is provided within the chamber. The bias power supply is electrically coupled to the substrate support and is configured to generate electrical bias energy. The electrical bias energy has a bias frequency. The waveform period of the electrical bias energy has a time length that is the reciprocal of the bias frequency. The high-frequency power supply is electrically connected to a high-frequency electrode and is configured to generate source high-frequency power for generating plasma from a gas within the chamber. The high-frequency power supply selects an initial frequency set obtained according to a specified process. The high-frequency power supply uses, in a first period, a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy. The high-frequency power supply adjusts, in a second period after the first period, a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy so as to reduce the power level of the reflected wave from the load of the source high-frequency power.

Advantages of the Invention

[0006] According to one exemplary embodiment, it is possible to reduce the power level of the reflected wave of the source high-frequency power.

Brief Description of the Drawings

[0007]

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DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, various exemplary embodiments will be described.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a bias power supply, and a high-frequency power supply. The substrate support is provided within the chamber. The bias power supply is electrically coupled to the substrate support and configured to generate electrical bias energy. The electrical bias energy has a bias frequency. The waveform period of the electrical bias energy has a time length that is the reciprocal of the bias frequency. The high-frequency power supply is electrically connected to a high-frequency electrode and configured to generate source high-frequency power to generate plasma from a gas within the chamber. The high-frequency power supply selects an initial frequency set obtained according to a specified process. The high-frequency power supply uses, in a first period, a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy. The high-frequency power supply adjusts, in a second period after the first period, a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy so as to reduce the power level of the reflected wave from the load of the source high-frequency power.

[0010] According to the above embodiment, in the first period, a plurality of frequencies included in the initial frequency set according to the specified process are used as the frequencies for each of the plurality of phase periods within the waveform period of the electrical bias energy. Therefore, when the specified process is being performed, the power level of the reflected wave of the source high-frequency power is reduced early. Also, in the second period after the first period, a plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy are adjusted, and the power level of the reflected wave from the load of the source high-frequency power is further reduced.

[0011] In one exemplary embodiment, the high-frequency power supply may be configured to select an initial frequency set from a plurality of frequency sets respectively corresponding to a plurality of processes. The high-frequency power supply may select, as the initial frequency set, the frequency set corresponding to the specified process when the frequency set corresponding to the specified process among the plurality of frequency sets is included.

[0012] In one exemplary embodiment, the waveform period of the electrical bias energy may be repeated in a second period. The high-frequency power supply may be configured to update the frequency set corresponding to the specified process with a frequency set including a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods obtained by repeating the waveform period.

[0013] In one exemplary embodiment, a plurality of process condition data sets for each of the plurality of processes and a plurality of frequency sets may be associated with each other and registered in a database.

[0014] In one exemplary embodiment, the database may be provided in the plasma processing apparatus or a server accessible by communication from both the plasma processing apparatus and other plasma processing apparatuses.

[0015] In one exemplary embodiment, each of the plurality of process condition data sets may include a plurality of condition items.

[0016] In one exemplary embodiment, a transformation matrix may be registered in the database. The transformation matrix minimizes the error between an output matrix obtained by multiplying it with an input matrix having a plurality of process condition data sets as a plurality of columns and a matrix having a plurality of frequency sets as a plurality of columns.

[0017] In one exemplary embodiment, the transformation matrix may be updated when a set of frequencies corresponding to a specified process is updated. The transformation matrix may be updated to minimize the error between the output matrix obtained by the product of the transformation matrix and the input matrix and a matrix having a plurality of sets of frequencies including the updated set of frequencies as a plurality of columns.

[0018] In one exemplary embodiment, the high-frequency power supply may be configured to generate an initial set of frequencies when a set of frequencies corresponding to a specified process is not included in the plurality of sets of frequencies. The high-frequency power supply may select, as the initial set of frequencies, a set of frequencies obtained by the product of the process condition data set of the specified process and the transformation matrix.

[0019] In one exemplary embodiment, each of the plurality of process condition data sets may include, as a plurality of condition items, at least one parameter of the pressure in the chamber, the power level of the source high-frequency power, the electrical bias energy, and the flow rate of each of one or more gases supplied into the chamber.

[0020] In one exemplary embodiment, the electrical bias energy may include pulses of voltage periodically generated at intervals having a bias frequency or a time length that is the reciprocal of the bias frequency. At least one parameter of the electrical bias energy may include type information indicating whether the electrical bias energy is bias high-frequency power or a pulse of voltage, the bias frequency, the power level of the bias high-frequency power, the duty ratio of the pulse of voltage, and the voltage level of the pulse of voltage.

[0021] In one exemplary embodiment, the plasma processing apparatus may further include a matcher including a matching circuit provided between the high-frequency power supply and the high-frequency electrode. Each of the plurality of process condition data sets may further include, as a plurality of condition items, the capacitance of at least one variable capacitor of the matching circuit.

[0022] In one exemplary embodiment, the plasma processing apparatus may be a capacitively coupled plasma processing apparatus. The plasma processing apparatus may further include an upper electrode provided above the substrate support and a DC power source connected to the upper electrode. Each of the plurality of process condition data sets may further include, as a plurality of condition items, the voltage level of the DC voltage applied from the DC power source to the upper electrode.

[0023] In one exemplary embodiment, the RF power source may use a frequency obtained by giving a frequency shift to suppress the power level of the reflected wave to the source frequency for the nth phase period within the mth waveform period of the electrical bias energy in the second period, as the source frequency for the nth phase period within the mth waveform period of the electrical bias energy before the mth waveform period of the source RF power. Here, "n" is from 1 to N, and "N" is the number of a plurality of phase periods within the waveform period of the electrical bias energy.

[0024] In one exemplary embodiment, the RF power source may sequentially use a plurality of candidate frequencies as the source frequency of the source RF power in the nth phase period within the waveform period of the electrical bias energy in the second period. The RF power source may select, as the source frequency of the source RF power for the nth phase period, the frequency that minimizes the power level of the reflected wave from the load of the source RF power among the plurality of candidate frequencies. Here, "n" is from 1 to N, and "N" is the number of a plurality of phase periods within the waveform period of the electrical bias energy.

[0025] In another exemplary embodiment, a power supply system is provided. The power supply system includes a bias power supply and a high-frequency power supply. The bias power supply is configured to generate electrical bias energy that is supplied to a substrate support provided in a chamber of a plasma processing apparatus. The electrical bias energy has a bias frequency. The waveform period of the electrical bias energy has a time length that is the reciprocal of the bias frequency. The high-frequency power supply is configured to generate source high-frequency power that is supplied to a high-frequency electrode to generate plasma from a gas in the chamber. The high-frequency power supply selects an initial frequency set corresponding to a specified process from a plurality of frequency sets respectively corresponding to a plurality of processes. The high-frequency power supply uses a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy in a first period. The high-frequency power supply adjusts a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy so as to reduce the power level of a reflected wave from the load of the source high-frequency power in a second period after the first period.

[0026] In yet another exemplary embodiment, a control method is provided. The control method includes a step (a) of supplying electrical bias energy having a bias frequency from a bias power source to a substrate support provided in a chamber of a plasma processing apparatus. The electrical bias energy has a bias frequency. The waveform period of the electrical bias energy has a time length that is the reciprocal of the bias frequency. The control method further includes a step (b) of supplying source high-frequency power from a high-frequency power source to a high-frequency electrode to generate plasma from a gas in the chamber. Step (b) includes a step of selecting an initial frequency set corresponding to a specified process from a plurality of frequency sets respectively corresponding to a plurality of processes. Step (b) further includes a step of using, for each of a plurality of phase periods within the waveform period of the electrical bias energy, a plurality of source frequencies of the source high-frequency power that are included in the initial frequency set, during a first period. Step (b) further includes a step of adjusting, during a second period after the first period, a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy so as to reduce the power level of a reflected wave from the load of the source high-frequency power.

[0027] In yet another exemplary embodiment, a program executed by a computer of the plasma processing apparatus is provided so that the above control method is executed by the plasma processing apparatus. In yet another exemplary embodiment, a storage medium storing this program is provided.

[0028] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0029] FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a main 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. Further, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas discharge port is connected to an exhaust system 40 described later. The substrate support unit 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0030] 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 plasma (Electron-Cyclotron-resonance plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like.

[0031] The main control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The main control unit 2 can be configured to control each element of the plasma processing apparatus 1 so as to execute the various processes described herein. In one embodiment, part or all of the main control unit 2 may be included in the plasma processing apparatus 1. The main control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The main control unit 2 is realized, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program includes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes of the control method according to the exemplary embodiment described later. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0032] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. FIG. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0033] 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 disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 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.

[0034] The substrate support unit 11 includes a main body 111 and a ring assembly 112. The main body 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 the substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0035] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member.

[0036] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0037] Further, the substrate support 11 may 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 disposed within the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support 11 may include a heat transfer gas supply unit configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0038] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. In addition to the shower head 13, the gas introduction part may include one or a plurality of side gas injectors (SGI) attached to one or a plurality of openings formed in the side wall 10a.

[0039] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure control type flow controller. Further, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one process gas.

[0040] The exhaust system 40 can be connected to, for example, a gas discharge port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0041] Hereinafter, with reference to FIG. 2, FIG. 3 will be referred to. FIG. 3 is a diagram schematically showing a plasma processing apparatus according to one exemplary embodiment. As shown in FIGS. 2 and 3, the power supply system 30 includes a high-frequency power supply 31 and a bias power supply 32.

[0042] The high-frequency power supply 31 constitutes the plasma generation unit 12 of one embodiment. The high-frequency power supply 31 is configured to generate a source high-frequency power RF. The source high-frequency power RF has a source frequency f RF . That is, the source high-frequency power RF has a sinusoidal waveform whose frequency is the source frequency f RF . The source frequency f RF can be a frequency within the range of 10 MHz to 150 MHz. The high-frequency power supply 31 is electrically connected to the high-frequency electrode via a matching unit 33, and is configured to supply the source high-frequency power RF to the high-frequency electrode. The high-frequency electrode may be a conductive member of the base 1110, at least one electrode provided in the ceramic member 1111a, or an upper electrode. When the source high-frequency power RF is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber 10.

[0043] The matching unit 33 has a matching circuit. The matching circuit of the matching unit 33 has a variable impedance. The matching circuit of the matching unit 33 may include a first variable capacitor 331 and a second variable capacitor 332. The first variable capacitor 331 is connected between a node 333 and the ground. The node 333 is provided on a power supply path connected between the high-frequency power supply 31 and the high-frequency electrode. The source high-frequency power RF is supplied to the high-frequency electrode via this power supply path. The second variable capacitor 332 is connected between the node 333 and the high-frequency electrode. The capacitance C1 of the first variable capacitor 331 and the capacitance C2 of the second variable capacitor 332 are controlled by the main control unit 2. The variable impedance of the matching unit 33 is set, for example, to reduce the reflection of the source high-frequency power RF from the load.

[0044] In one embodiment, the high-frequency power supply 31 may include a signal generator 31g, a D / A converter 31c, and an amplifier 31a. The signal generator 31g is configured to generate a high-frequency signal. The signal generator 31g may include a processor. The D / A converter 31c is configured to perform D / A conversion on the high-frequency signal (digital signal) output from the signal generator 31g. The amplifier 31a is configured to amplify the high-frequency signal (analog signal) from the D / A converter 31c to generate the source high-frequency power RF.

[0045] The bias power supply 32 is configured to generate an electrical bias energy BE. The bias power supply 32 is electrically coupled to the substrate support 11. The bias power supply 32 is electrically connected to a bias electrode in the substrate support 11 and is configured to supply the electrical bias energy BE to the bias electrode. The bias electrode may be at least one electrode provided in the conductive member or ceramic member 1111a of the base 1110. When the electrical bias energy BE is supplied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0046] The electrical bias energy BE has a bias frequency. The bias frequency is lower than the source frequency. The bias frequency may be a frequency within the range of 100 kHz to 60 MHz, for example, 400 kHz. The electrical bias energy BE has a waveform period, i.e., a period CY. The period CY has a time length that is the reciprocal of the bias frequency. The electrical bias energy BE is periodically supplied to the bias electrode at the period CY (time interval).

[0047] Referring now to FIG. 4, together with FIGS. 2 and 3. FIG. 4 is an exemplary timing chart of the waveform of the electrical bias energy. The electrical bias energy BE may be a bias high-frequency power LF having a bias frequency. That is, the electrical bias energy BE may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply 32 is electrically connected to the bias electrode via the matcher 34. The variable impedance of the matching circuit of the matcher 34 is set, for example, to reduce reflection from the load of the bias high-frequency power LF.

[0048] Alternatively, the electrical bias energy BE may include voltage pulses PV that are periodically generated at time intervals of the period CY. The waveform of the pulse PV in the electrical bias energy BE may have a rectangular wave, a triangular wave, or any waveform. The polarity of the voltage of the pulse PV of the electrical bias energy BE is set so as to generate a potential difference between the substrate W and the plasma and to draw ions from the plasma into the substrate W. The pulse PV of the electrical bias energy BE may be, for example, a pulse of negative voltage. The pulse PV of the electrical bias energy BE may be generated by waveform shaping using a pulse unit with respect to the DC voltage from a DC power supply.

[0049] As shown in FIG. 2, the plasma processing apparatus 1 may further include a power supply 38. The power supply 38 is electrically connected to the upper electrode. The power supply 38 is configured to apply a negative DC voltage. The power supply 38 may be a DC power supply.

[0050] As shown in FIGS. 2 and 3, the plasma processing apparatus 1 further includes a sensor 35 and a sensor 36. The sensor 35 is configured to measure the power level Pr of the reflected wave from the load of the source high-frequency power RF. The sensor 35 includes, for example, a directional coupler and an A / D converter. The directional coupler may be provided between the high-frequency power supply 31 and the matcher 33. The A / D converter generates a digital value of the power level Pr measured by the directional coupler. The power level Pr (digital value) of the reflected wave measured by the sensor 35 is notified to the high-frequency power supply 31. In addition, the power level Pf (digital value) of the traveling wave may be notified from the sensor 35 to the high-frequency power supply 31.

[0051] The sensor 36 includes a voltage sensor and a current sensor. The sensor 36 is configured to measure the voltage V RF and the current I RF in the power supply path connecting the high-frequency power supply 31 and the high-frequency electrode to each other. The source high-frequency power RF is supplied to the high-frequency electrode via this power supply path. The sensor 36 may be provided between the high-frequency power supply 31 and the matcher 33. The sensor 36 further includes an A / D converter. The A / D converter generates digital values of the voltage V RF and the current I RF respectively. The voltage V RF (digital value) and the current I RF (digital value) are notified to the high-frequency power supply 31.

[0052] Hereinafter, with reference to FIGS. 2 and 3, FIGS. 5(a) and 5(b) will be referred to. Each of FIGS. 5(a) and 5(b) is a timing chart of an example of source high-frequency power and electrical bias energy in a plasma processing apparatus according to one exemplary embodiment. In these figures, "ON" of the source high-frequency power RF indicates that the source high-frequency power RF is being supplied, and "OFF" of the source high-frequency power RF indicates that the supply of the source high-frequency power RF has been stopped. Also, in these figures, "ON" of the electrical bias energy BE indicates that the electrical bias energy BE is being supplied, and "OFF" of the electrical bias energy BE indicates that the supply of the electrical bias energy BE has been stopped.

[0053] The high-frequency power supply 31 is configured to supply the source high-frequency power RF in parallel with the periodic supply of the electrical bias energy BE from the bias power supply 32. That is, as shown in FIG. 5(a), the electrical bias energy BE and the source high-frequency power RF may be supplied simultaneously and continuously from the start to the end of the process. Hereinafter, the period from the start to the end of the process during which the electrical bias energy BE and the source high-frequency power RF are supplied simultaneously and continuously will be referred to as the continuous supply period P C is called.

[0054] Alternatively, as shown in FIG. 5(b), the pulses of the electrical bias energy BE and the pulses of the source high-frequency power RF may be supplied in synchronization with each other. That is, in each of the pulse periods PP1, PP2, PP3,... (i.e., a plurality of pulse periods PP), the electrical bias energy BE and the source high-frequency power RF may be supplied simultaneously. Each of the plurality of pulse periods PP includes a plurality of cycles CY. That is, in each of the plurality of pulse periods PP, the electrical bias energy BE is supplied periodically.

[0055] The high-frequency power supply 31 is the source frequency f of the source high-frequency power RF for each of the plurality of phase periods SP within each cycle CY RFis configured to adjust. The source frequency f in the high-frequency power supply 31 RF may be adjusted by adjusting the frequency of the high-frequency signal by the signal generator 31g. The plurality of phase periods SP are a plurality of periods that divide the period CY. As shown in FIG. 4, each period CY is divided into a plurality of phase periods SP, namely, phase periods SP1 to SP N . "N" is the number of phase periods in each period CY.

[0056] The high-frequency power supply 31 synchronizes with the bias power supply 32 using a synchronization signal for setting the source frequency f RF for each of the plurality of phase periods SP. The synchronization signal may be supplied from the high-frequency power supply 31 (or the signal generator 31g) to the bias power supply 32, or may be supplied from the bias power supply 32 to the high-frequency power supply 31. Alternatively, the synchronization signal may be supplied from another device to the high-frequency power supply 31 and the bias power supply 32.

[0057] FIG. 6 is a diagram showing a waveform of an example of electrical bias energy in a plasma processing apparatus according to one exemplary embodiment. The continuous supply period P C includes, as shown in FIG. 6, a first period P1 and a second period P2. The first period P1 includes at least one period CY. In the illustrated example, the first period P1 includes one period CY1. The second period P2 is a period after the first period P1 and includes a plurality of periods CY. In the illustrated example, the second period P2 includes periods CY2 to CY M . The continuous supply period P C may further include an ignition period P IG . The ignition period P IG is a period before the first period P1 and includes at least one period CY.

[0058] During the ignition period P IG , the high-frequency power supply 31 uses a plurality of frequencies included in a frequency set for the prepared ignition period P RF as a plurality of source frequencies f IG for each of the plurality of phase periods SP within each period CY. The ignition period PIG The frequency set to be used may be registered in the database 50 described later, may be stored in the storage unit 2a2 of the main control unit 2, or may be stored in the storage unit within the high-frequency power supply 31.

[0059] During the first period P1, the high-frequency power supply 31 uses a plurality of source frequencies f for each of the plurality of phase periods SP within each cycle CY. RF as a plurality of frequencies included in the initial frequency set. When there is a frequency set corresponding to the process specified by the main control unit 2 among the plurality of frequency sets registered in the database 50, the high-frequency power supply 31 selects the frequency set corresponding to the specified process as the initial frequency set. The database 50 may be provided in the storage unit 2a2, or may be provided in the storage unit within the high-frequency power supply 31. Alternatively, the database 50 may be provided in the plasma processing apparatus 1 or in a server 100 that can be accessed by communication from both the plasma processing apparatus 1 and other plasma processing apparatuses.

[0060] FIGS. 7(a) and 7(b) are diagrams showing a database used in a plasma processing apparatus according to one exemplary embodiment. As shown in FIGS. 7(a) and 7(b), the database 50 associates a plurality of process condition data sets for each of the plurality of processes with a plurality of frequency sets. In the illustrated example, a plurality of process condition data sets for each of the plurality of processes are associated with a plurality of process IDs that respectively identify the plurality of processes. Also, a plurality of frequency sets for each of the plurality of processes are associated with a plurality of process IDs that respectively identify the plurality of processes.

[0061] In the example shown in FIG. 7(a), X process condition data sets are registered in the database 50. Each process condition data set includes Y condition items. For example, the process condition data set for the process with the process ID "1" includes the condition items b 11 ~b Y1It includes. Also, the process condition data set for the process with the process ID of "X" has condition items b 1X ~b YX It includes. The multiple condition items of each process condition data set may include at least one parameter of the pressure in chamber 10, the power level of the source high-frequency power RF, the electrical bias energy BE, and the flow rate of each of one or more gases supplied into chamber 10. At least one parameter of the electrical bias energy BE may include type information indicating whether the electrical bias energy BE is the bias high-frequency power LF or the voltage pulse PV, the bias frequency, the power level of the bias high-frequency power LF, the duty ratio of the voltage pulse PV, and the voltage level of the voltage pulse PV. The identification information is a numerical value that specifies the type (bias high-frequency power LF or voltage pulse PV) of the electrical bias energy BE. Also, the multiple condition items of each process condition data set may further include capacitance C1 and / or capacitance C2. Also, the multiple condition items of each process condition data set may further include the voltage level of the DC voltage applied from power supply 38 to the upper electrode.

[0062] In the example shown in Fig. 7(b), X frequency sets are registered in database 50. Each frequency set includes N frequencies. For example, the frequency set for the process with the process ID of "1" includes frequencies f 11 ~f N1 It includes. Also, the frequency set for the process with the process ID of "X" includes frequencies f 1X ~f NX It includes. Each frequency set is prepared in advance so as to reduce the power level of the reflected wave from the load of the source high-frequency power RF when used as the multiple source frequencies f RF for each of the multiple phase periods SP within the period CY in the corresponding process.

[0063] When the frequency set corresponding to the process (process ID) specified by the main control unit 2 is not registered in the database 50, the high-frequency power supply 31 may select another frequency set as the initial frequency set. For example, the high-frequency power supply 31 may select, as the initial frequency set, the frequency set corresponding to the process having the process condition data set closest to the process condition data set of the specified process among the plurality of frequency sets in the database 50. Alternatively, the high-frequency power supply 31 may select, as the initial frequency set, the frequency set obtained by multiplying the process condition data set of the specified process by the conversion matrix described later.

[0064] In the second period P2, the high-frequency power supply 31 adjusts a plurality of source frequencies f for each of the plurality of phase periods SP within each cycle CY so as to reduce the power level of the reflected wave from the load of the source high-frequency power RF. RF Adjust.

[0065] In the first example, for the source frequency f for the nth phase period SP within the mth cycle CY in the second period P2, the high-frequency power supply 31 uses the frequency obtained by applying a frequency shift to the source frequency f for the phase period SP within the cycle CY preceding the cycle CY so as to suppress the power level of the reflected wave. Note that, in one example, the cycle CY preceding the cycle CY is the cycle CY. Details of the adjustment of the source frequency f in the first example will be described later. m Within the nth phase period SP n For the source frequency f RF As the cycle CY m For the phase period SP within the cycle CY preceding the cycle CY n For the source frequency f RF To the source frequency f for the phase period SP within the cycle CY preceding the cycle CY, the high-frequency power supply 31 uses the frequency obtained by applying a frequency shift to suppress the power level of the reflected wave. Note that, in one example, the cycle CY preceding the cycle CY is the cycle CY. Details of the adjustment of the source frequency f in the first example will be described later. m The cycle CY preceding the cycle CY is, in one example, the cycle CY m-1 For the source frequency f in the first example RF Details of the adjustment will be described later.

[0066] In the second example, in the nth phase period SP within at least one cycle CY in the second period P2, the high-frequency power supply 31 sequentially uses a plurality of candidate frequencies as the source frequency f. n In the nth phase period SP RF For the source frequency f n For the phase period SP RFAs such, a frequency that minimizes the power level of the reflected wave from the load of the source high-frequency power RF among a plurality of candidate frequencies is selected. The high-frequency power supply 31 has a source frequency f n for the phase period SP RF and uses the selected frequency as the source frequency f n for the phase period SP RF in each of the other cycles CY in the second period P2.

[0067] When the pulse of the electrical bias energy BE and the pulse of the source high-frequency power RF are supplied synchronously with each other, each of the pulse periods PP1 to the pulse period PP J includes a firing period P C similar to the continuous supply period P IG , a first period P1, and a second period P2. The high-frequency power supply 31 sets a source frequency f J for each of the plurality of phase periods SP within each cycle CY in each of the pulse periods PP1 to the pulse period PP C in the same manner as the continuous supply period P RF . However, the high-frequency power supply 31 may use, as an initial frequency set, the plurality of source frequencies f J for each of the plurality of phase periods SP obtained in the final cycle CY of the pulse period PP1 in the first period P1 of the pulse periods PP2 to the pulse period PP RF . Note that the pulse period PP J may be the pulse period PP2 or a pulse period after the pulse period PP2.

[0068] FIG. 8 is a diagram showing an example of the waveform of the electrical bias energy in a plasma processing apparatus according to one exemplary embodiment. Each of the pulse periods PP J+1 to PP K includes a firing period P C similar to the continuous supply period P IG , a first period P1, and a second period P2, as shown in FIG. 8. Each of the pulse periods PP J+1 to PP K has a transition period P IG between the firing period PT further includes. Note that the pulse period PP J+1 may be the pulse period PP3, or may be a pulse period after the pulse period PP3.

[0069] The high-frequency power supply 31 has a pulse period PP J+1 ~PP K For each ignition period P IG in, for the pulse periods PP1 to PP J similar to each of, the source frequency f for each of the plurality of phase periods SP within each cycle CY RF is set.

[0070] The high-frequency power supply 31 has a pulse period PP J+1 ~PP K For each of (pulse period PP k ), in the transition period P T the source frequency f for each phase period SP within each cycle CY RF is adjusted according to the degree of reflection of the source high-frequency power RF in the same phase period SP within the same cycle CY in the pulse period before the pulse period PP k . The pulse period before the pulse period PP k is, for example, the immediately preceding pulse period, i.e., the pulse period PP k-1 . Details regarding the adjustment of the source frequency f for each phase period SP within each cycle CY in the transition period P T will be described later. RF

[0071] The high-frequency power supply 31 has a pulse period PP J+1 ~PP K For each of (pulse period PP k ) in the first period P1 and the second period P2, similar to the first period P1 and the second period P2 of the pulse period PP J the source frequency f for each of the plurality of phase periods SP within each cycle CY is set. Note that the high-frequency power supply 31, in the first period P1 of the pulse period PP RF , in the first period P1 of the pulse period PP k k-1A plurality of source frequencies f for each of the plurality of phase periods SP obtained in the final cycle CY RF may be used as an initial frequency set.

[0072] According to the plasma processing apparatus 1, in the first period P1, a plurality of frequencies included in the initial frequency set corresponding to the designated process are used as the frequencies for each of the plurality of phase periods SP within the cycle CY. Therefore, when the designated process is being performed, the power level of the reflected wave of the source high-frequency power RF is reduced early. Also, in the second period P2 after the first period P1, a plurality of source frequencies f RF for each of the plurality of phase periods SP within the cycle CY are adjusted so that the power level of the reflected wave from the load of the source high-frequency power RF is further reduced.

[0073] In one exemplary embodiment, the high-frequency power supply 31 (or the signal generator 31g) may update the frequency set in the database 50 corresponding to the designated process. The frequency set in the database 50 corresponding to the designated process is updated with a frequency set including a plurality of source frequencies f RF for each of the plurality of phase periods SP finally obtained by repeating the cycle CY.

[0074] Refer to FIGS. 9(a) and 9(b) below. FIG. 9(a) is a diagram showing a database used in a plasma processing apparatus according to one exemplary embodiment, and FIG. 9(b) is a diagram for explaining a conversion matrix. In one embodiment, the conversion matrix A shown in FIG. 9(a) may be further registered in the database 50. The conversion matrix A includes elements of N rows × Y columns. As shown in FIG. 9(b), the conversion matrix A is set so as to minimize the error between the output matrix O obtained by the product of the conversion matrix A and the input matrix B and the matrix F. The input matrix B has a plurality of process condition data sets registered in the database 50 as a plurality of columns. The matrix F has a plurality of frequency sets registered in the database 50 as a plurality of columns. The conversion matrix A is obtained, for example, by the least squares method. The conversion matrix A may be obtained in the high-frequency power supply 31 or the signal generator 31g, the main control unit 2, or the server 100 and registered in the database 50.

[0075] In one embodiment, the conversion matrix A may be updated when the frequency set corresponding to the specified process is updated. The conversion matrix A is updated so as to minimize the error between the output matrix O obtained by the product of the conversion matrix A and the input matrix B and the matrix F including a plurality of frequency sets including the updated frequency set as a plurality of columns. The conversion matrix A is obtained, for example, by the least squares method. The conversion matrix A may be obtained in the high-frequency power supply 31 or the signal generator 31g, the main control unit 2, or the server 100 and registered in the database 50.

[0076] According to the plasma processing apparatus 1, it becomes possible to easily obtain a frequency set including a plurality of source frequencies f for each of a plurality of phase periods SP of each cycle CY in a new process. Specifically, the frequency set including a plurality of source frequencies f for each of a plurality of phase periods SP of each cycle CY in a new process RF is obtained by the product of the conversion matrix A and an input matrix including a process condition data set of the new process. RF

[0077] Hereinafter, with reference to FIG. 10, a control method according to one exemplary embodiment will be described. FIG. 10 is a flowchart showing a control method according to one exemplary embodiment. In the control method shown in FIG. 10 (hereinafter referred to as "method MT"), each part of the plasma processing apparatus 1 is controlled by the main control unit 2 so as to perform the process specified by the main control unit 2 under the process conditions of the process.

[0078] Method MT includes step STa and step STb. In step STa, electrical bias energy BE is supplied to the substrate support 11. The electrical bias energy BE is periodically supplied at a period CY. In step STb, source high-frequency power is supplied from the high-frequency power supply 31 to the high-frequency electrode in order to generate plasma from the gas in the chamber 10.

[0079] Step STb includes step STb1, step STb2, and step STb3. In step STb1, an initial frequency set corresponding to the specified process is selected from a plurality of frequency sets respectively corresponding to a plurality of processes. As described above, the plurality of frequency sets are registered in the database 50. Step STb2 is performed in the first period P1. In step STb2, for each of the plurality of phase periods SP within each period CY, a plurality of source frequencies f RF as a plurality of frequencies included in the initial frequency set are used.

[0080] Step STb3 is performed in the second period P2. In step STb3, for each of the plurality of phase periods SP within each period CY, a plurality of source frequencies f RF are adjusted so as to reduce the power level of the reflected wave from the load of the source high-frequency power RF. The adjustment of the plurality of source frequencies f RF for each of the plurality of phase periods SP within each period CY in the second period P2 is performed according to the first example or the second example described above.

[0081] Hereinafter, with reference to FIGS. 11 and 12, a plurality of source frequencies f for each of the plurality of phase periods SP within each period CY in the second period P2RF A first example of an adjustment method will be described in detail. Each of FIGS. 11 and 12 is a flowchart showing a first example of the adjustment of a plurality of source frequencies for each of a plurality of phase periods of each waveform period in a second period.

[0082] Step ST1 of the adjustment method (hereinafter referred to as "method MTA") shown in each of FIGS. 11 and 12 is performed in the first period P1. In step ST1, source high-frequency power RF is supplied. In the first period P1, as described above, a plurality of source frequencies f RF as a plurality of frequencies included in the initial frequency set are used.

[0083] In the subsequent step ST2, m is set to 1. Then, steps ST3 to ST5 are performed. Steps ST3 to ST5 are performed while n is set to each of 1 to N in order.

[0084] In step ST3, it is determined whether Pr[m, n] is greater than Pth[n]. Pr[m, n] is a representative value of the power level of the reflected wave of the source high-frequency power RF in the nth phase period SP m within the mth cycle CY n . The representative value can be an average value or a maximum value. Pth[n] is a threshold value for the phase period SP n and is predetermined. When Pr[m, n] is greater than Pth[n], that is, when the power level of the reflected wave in the phase period SP m within the cycle CY n is large, step ST4 is performed. On the other hand, when Pr[m, n] is less than or equal to Pth[n], that is, when the power level of the reflected wave in the phase period SP m within the cycle CY n is small, step ST5 is performed.

[0085] As shown in FIG. 11, in step ST4, f RF [m + 1, n] is set to the sum of f RF [m, n] and Δf[m + 1, n]. f RF[m,n] is the period CY m Phase period SP n For source frequency f RF Δf[m,n] is the source frequency f RF To determine [m,n], f RF It is a frequency shift added to [m-1,n], and its initial value (i.e., Δf[2,n]) is predetermined.

[0086] Alternatively, in step ST4, Δf[m+1,n] is set to α[m+1,n]*(Pr[m,n]-Pth[n]), as shown in FIG. m+1 nth phase period in SP n Δf[m+1,n] is a coefficient for which the initial value (i.e., α[2,n]) is determined in advance. In step ST4 shown in FIG. 12, Δf[m+1,n] is set to a value corresponding to the difference between the power level of the reflected wave and the threshold value. Then, in step ST4 shown in FIG. 12, f RF [m+1,n] is f RF It is set to the sum of [m,n] and Δf[m+1,n].

[0087] As shown in FIG. 11 and FIG. 12, in step ST5, RF [m+1,n] is f RF Set to the same value as [m,n].

[0088] In the subsequent step ST6, m is incremented by 1, and a second period P2 starts. Then, steps ST7 to ST13 are performed. Steps ST7 to ST13 are performed while n is successively set to 1 to N. In step ST7, the source high frequency power RF is increased in a cycle CY m It is supplied in the cycle CY m Phase period SP n At source frequency f RF f RF It is set to [m,n].

[0089] In the next step ST8, the cycle CY m Phase period SP nThe power level of the reflected wave in is greater than that in the same phase period SP within the previous cycle CY (for example, cycle CY m-1 ) is determined whether it has increased to an unacceptable level from the power level of the reflected wave in. As an example, in step ST8, it is determined whether the difference between Pr[m,n] and Pr[m - 1,n] is greater than ΔdPth[n]. ΔdPth[n] is the threshold for the nth phase period SP n and is predetermined. ΔdPth[n] may be zero. n

[0090] If the determination result of step ST8 is "YES", that is, when the power level of the reflected wave in the phase period SP within cycle CY m has increased to an unacceptable level, step ST9 is performed. As shown in FIG. 11, in step ST9, Δf[m + 1,n] is set to -Δf[m,n]. That is, in step ST9, the direction of the frequency shift is set to the opposite direction. In other words, in step ST9, the frequency shift is changed from one of the positive frequency shift and the negative frequency shift to the other. Alternatively, as shown in FIG. 12, in step ST9, α[m + 1,n] is set to -α[m,n]. n

[0091] On the other hand, if the determination result of step ST8 is "NO", that is, when the power level of the reflected wave in the phase period SP within cycle CY m is acceptable, step ST10 is performed. In step ST10, as shown in FIG. 11, Δf[m + 1,n] is set to the same value as Δf[m,n]. Alternatively, as shown in FIG. 12, in step ST10, α[m + 1,n] is set to the same value as α[m,n]. n

[0092] In the subsequent step ST11, it is determined whether Pr[m,n] is greater than Pth[n]. If Pr[m,n] is greater than Pth[n], that is, within the phase period SP within cycle CY m nWhen the power level of the reflected wave in is high, step ST12 is performed. On the other hand, when Pr[m,n] is less than or equal to Pth[n], that is, within the phase period SP m during the cycle CY n when the power level of the reflected wave is low, step ST13 is performed.

[0093] As shown in FIG. 11, in step ST12, f RF [m + 1,n] is set to the sum of f RF [m,n] and Δf[m + 1,n]. Alternatively, in step ST12, as shown in FIG. 12, Δf[m + 1,n] is set to α[m + 1,n]*(Pr[m,n] - Pth[n]). That is, in step ST12 shown in FIG. 12, Δf[m + 1,n] is set to a value corresponding to the difference between the power level of the reflected wave and the threshold. And in step ST12 shown in FIG. 12, f RF [m + 1,n] is set to the sum of f RF [m,n] and Δf[m + 1,n].

[0094] As shown in FIGS. 11 and 12, in step ST13, f RF [m + 1,n] is set to the same value as f RF [m,n].

[0095] In the subsequent step ST14, it is determined whether m is equal to M. That is, it is determined whether the processing regarding the final cycle CY in the second period P2 has been completed. If the processing regarding the final cycle CY has not been completed, the processing from step ST6 is repeated. On the other hand, if the processing regarding the final cycle CY has been completed, the method MTA ends.

[0096] As described above, in the method MTA, the frequency shift for the phase period SP m during the m-th cycle CY n is adjusted according to the change in the power level of the reflected wave of the source high-frequency power RF during the same phase period SP m in each of the two cycles CY preceding the cycle CY. n

[0097] Note that the direction of the frequency shift Δf[m,n] may be the same as the direction of the frequency shift Δf[m-1,n]. In this case, within the period CY m the phase period SP n if the representative value of the power level of the reflected wave of the source high-frequency power RF is greater than the threshold value, then f RF [m+1,n] may be set to an intermediate frequency (e.g., the average value) between f RF [m-1,n] and f RF [m,n]. Also, when using the intermediate frequency as the source frequency f RF [m+1,n], if the representative value of the power level of the reflected wave of the source high-frequency power RF is greater than the threshold value, then the direction of the frequency shift Δf[m+2,n] is set to the opposite direction of the frequency shift Δf[m,n], and the absolute value of the frequency shift Δf[m+2,n] may be set to an absolute value greater than the absolute value of the frequency shift Δf[m,n]. In this case, it is possible to avoid the situation where the reflection amount of the source high-frequency power RF cannot be reduced from the local minimum value.

[0098] Hereinafter, with reference to FIGS. 13 and 14, for each of the plurality of phase periods SP within each period CY during the transition period P T the adjustment method of the plurality of source frequencies f RF will be described in detail. Each of FIGS. 13 and 14 is a flowchart showing an example of the adjustment method of the source frequency for a plurality of phase periods within each waveform period during the transition period.

[0099] In step ST32 of the adjustment method (hereinafter referred to as "method MTB") shown in each of FIGS. 13 and 14, k is set to 2. Then, steps ST33 to ST35 are performed. Steps ST33 to ST35 are performed while m is sequentially changed to each of 1 to M T and n is sequentially changed to each of 1 to N. M T is the number of periods CY within the transition period P T .

[0100] In engineering ST33, it is determined whether Pr[k,m,n] is greater than Pth[n]. Pr[k,m,n] is the power level representative value of the reflected wave of the source high-frequency power RF in the nth phase period SP within the mth cycle CY in the kth pulse period PP. k in the mth cycle CY m within the nth phase period SP n The representative value can be the average value or the maximum value. Pth[n] is the threshold for the nth phase period SP and is predetermined. If Pr[k,m,n] is greater than Pth[n], that is, when the power level of the reflected wave in the phase period SP within the cycle CY in the pulse period PP is high, process ST34 is performed. On the other hand, if Pr[k,m,n] is less than or equal to Pth[n], that is, when the power level of the reflected wave in the phase period SP within the cycle CY in the pulse period PP is low, process ST35 is performed. n For the threshold value of, and is predetermined. If Pr[k,m,n] is greater than Pth[n], that is, when the power level of the reflected wave in the phase period SP within the cycle CY in the pulse period PP is high, process ST34 is performed. On the other hand, if Pr[k,m,n] is less than or equal to Pth[n], that is, when the power level of the reflected wave in the phase period SP within the cycle CY in the pulse period PP is low, process ST35 is performed. k in the cycle CY m within the phase period SP n in the cycle CY k in the cycle CY m within the phase period SP n in the cycle CY

[0101] As shown in FIG. 13, in process ST34, f RF [k + 1,m,n] is set to the sum of f RF [k,m,n] and Δf[k + 1,m,n]. f RF [k,m,n] is the source frequency f k for the phase period SP within the cycle CY in the pulse period PP m within the cycle CY n for the phase period SP within the cycle CY in the pulse period PP RF is. Δf[k,m,n] is the frequency shift added to f RF [k,m,n] for the determination of f RF [k - 1,m,n], and its initial value (i.e., Δf[3,m,n]) is predetermined.

[0102] Alternatively, in process ST34, as shown in FIG. 14, Δf[k + 1,m,n] is set to β[k + 1,m,n]*(Pr[k,m,n] - Pth[n]). β[k + 1,m,n] is the cycle CY k in the pulse period PP mInternal phase period SP n is a coefficient for which the initial value (i.e., β[3,m,n]) is predetermined. In step ST34 shown in FIG. 14, Δf[k+1,m,n] is set to a value corresponding to the difference between the power level of the reflected wave and the threshold value. And in step ST34 shown in FIG. 14, f RF [k+1,m,n] is set to the sum of f RF [k,m,n] and Δf[k+1,m,n].

[0103] As shown in FIGS. 13 and 14, in step ST35, f RF [k+1,m,n] is set to the same value as f RF [k,m,n].

[0104] In the subsequent step ST36, k is incremented by 1. Then, steps ST37 to ST43 are performed. Steps ST37 to ST43 are performed while m is sequentially changed to each of 1 to M T and n is sequentially changed to each of 1 to N. In step ST37, the source high-frequency power RF is supplied during the pulse period PP k . During the phase period SP k within the period CY m in the pulse period PP n , the source frequency f RF is set to f RF [k,m,n].

[0105] In the subsequent step ST38, the power level of the reflected wave during the phase period SP k within the period CY m in the pulse period PP n is the same as that in the same phase period SP k in the previous pulse period PP k-1 (for example, the pulse period PP m ) within the same period CY nIt is determined whether the power level of the reflected wave in the n-th phase period SP has increased to an unacceptable extent. As an example, in step ST38, it is determined whether the difference between Pr[k,m,n] and Pr[k-1,m,n] is greater than ΔdPth[n]. ΔdPth[n] is the power level of the reflected wave in the n-th phase period SP n ΔdPth[n] is a threshold value for the Pth[n], which is determined in advance. ΔdPth[n] may be zero.

[0106] If the determination result of step ST38 is "YES", that is, the pulse period PP k CY m Phase period SP n If the power level of the reflected wave at has increased to an unacceptable level, step ST39 is performed. As shown in FIG. 13, in step ST39, Δf[k+1,m,n] is set to −Δf[k,m,n]. That is, in step ST39, the direction of the frequency shift is set to the opposite direction. In other words, in step ST39, the frequency shift is changed from one of the positive frequency shift and the negative frequency shift to the other frequency shift. Alternatively, as shown in FIG. 14, in step ST39, β[k+1,m,n] is set to −β[k,m,n].

[0107] On the other hand, if the determination result of step ST38 is "NO", that is, during the pulse period PP k CY m Phase period SP n If the power level of the reflected wave at is tolerable, step ST40 is performed. In step ST40, Δf[k+1,m,n] is set to the same value as Δf[k,m,n], as shown in Fig. 13. Alternatively, in step ST40, β[k+1,m,n] is set to the same value as β[k,m,n], as shown in Fig. 14.

[0108] In the next step ST41, it is determined whether Pr[k,m,n] is greater than Pth[n]. If Pr[k,m,n] is greater than Pth[n], that is, if the period CY m Phase period SP nWhen the power level of the reflected wave in [description] is high, step ST42 is performed. On the other hand, when Pr[k,m,n] is less than or equal to Pth[n], that is, within the phase period SP m in the cycle CY n when the power level of the reflected wave is low, step ST43 is performed.

[0109] As shown in FIG. 13, in step ST42, f RF [k + 1,m,n] is set to the sum of f RF [k,m,n] and Δf[k + 1,m,n]. Alternatively, in step ST42, as shown in FIG. 14, Δf[k + 1,m,n] is set to β[k + 1,m,n]*(Pr[k,m,n] - Pth[n]). That is, in step ST42 shown in FIG. 14, Δf[k + 1,m,n] is set to a value corresponding to the difference between the power level of the reflected wave and the threshold. And in step ST14 shown in FIG. 14, f RF [k + 1,m,n] is set to the sum of f RF [k,m,n] and Δf[k + 1,m,n].

[0110] As shown in FIGS. 13 and 14, in step ST43, f RF [k + 1,m,n] is set to the same value as f RF [k,m,n].

[0111] In the subsequent step ST44, it is determined whether k is equal to K. That is, it is determined whether the processing regarding the final pulse period PP K has been completed. If the processing regarding the final pulse period PP K has not been completed, the processing from step ST36 is repeated. On the other hand, if the processing regarding the final pulse period PP K has been completed, the method MTB ends.

[0112] As described above, in the method MTB, the frequency shift for the phase period SP k in the m-th cycle CY m within the pulse period PP n is for the pulse period PP kThe same cycle CY of each of the two pulse periods PP before m The same phase period SP within n It is adjusted according to the change in the power level of the reflected wave of the source high-frequency power RF in

[0113] Note that there may be a case where the direction of the frequency shift Δf[k,m,n] is the same as the direction of the frequency shift Δf[k - 1,m,n]. In this case, for the pulse period PP k The cycle CY within m The phase period SP within n If the representative value of the power level of the reflected wave of the source high-frequency power RF is greater than the threshold value, then f RF [k + 1,m,n] may be set to an intermediate frequency (for example, the average value) between f RF [k - 1,m,n] and f RF [k,m,n]. Also, when using the intermediate frequency as the source frequency f RF [k + 1,m,n], if the representative value of the power level of the reflected wave of the source high-frequency power RF is greater than the threshold value, then the direction of the frequency shift Δf[k + 2,m,n] is set to the opposite direction of the frequency shift Δf[k,m,n], and the absolute value of the frequency shift Δf[k + 2,m,n] may be set to an absolute value greater than the absolute value of the frequency shift Δf[k,m,n]. In this case, it is possible to avoid the situation where the reflection amount of the source high-frequency power RF cannot be reduced from the local minimum value.

[0114] As described above, various exemplary embodiments have been described. However, without being limited to the above-described exemplary embodiments, various additions, omissions, substitutions, and changes may be made. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0115] In another embodiment, the plasma processing apparatus may be an inductively coupled plasma processing apparatus, an ECR plasma processing apparatus, a helicon wave-excited plasma processing apparatus, or a surface wave plasma processing apparatus. In any plasma processing apparatus, the source high-frequency power RF is used for plasma generation.

[0116] Also, in method MTA and method MTB, the phase period SP n As a representative value in, the phase period SP n The representative value of the power level of the reflected wave of the source high-frequency power RF in is used. The phase period SP n The representative value in may be any value as long as it can represent the degree of reflection of the source high-frequency power RF in the phase period SP n Another representative value in the phase period SP n may be a representative value (for example, an average value or a maximum value) of the ratio of the power level Pr of the reflected wave to the output power level of the source high-frequency power RF. Alternatively, another representative value in the phase period SP n may be a representative value (for example, an average value or a maximum value) of the phase difference between the voltage and current acquired by the sensor 36.

[0117] Also, in the database 50, a plurality of frequency sets for each of the ignition period P C within the continuous supply period P IG and all cycles CY included in the first period P1 may be stored in association with the process (process ID). The high-frequency power supply 31 may use a plurality of frequency sets corresponding to the specified process (process ID) in the ignition period P C within the continuous supply period P IG and all cycles CY included in the first period P1, respectively. In this case, the conversion matrix A may be a matrix including elements of (L×N) rows × Y rows. Here, "L" is the number of the plurality of frequency sets, which is the number of the ignition period P C within the continuous supply period P IG and all cycles CY included in the first period P1. In this case, each of the output matrix O and the matrix F includes elements of (L×N) rows × X rows.

[0118] Also, in the database 50, a single set of frequency groups commonly used in all of the plurality of pulse periods PP1 to PP K may be stored in association with a process (process ID). The single set of frequency groups includes a plurality of frequency sets. The high-frequency power supply 31 may use the plurality of frequency sets included in the single set of frequency groups in each of the plurality of pulse periods PP1 to PP K during the ignition period P IG and all cycles included in the first period P1, respectively. Also in this case, the conversion matrix A may be a matrix including elements of (L×N) rows × Y rows. Here, "L" is the number of the plurality of frequency sets included in the single set of frequency groups, and is the number of all cycles CY included in the ignition period P K and the first period P1 in each of the plurality of pulse periods PP1 to PP IG In this case, each of the output matrix O and the matrix F includes elements of (L×N) rows × X rows.

[0119] Also, in the database 50, a plurality of sets of frequency groups for each of the plurality of pulse periods PP1 to PP K may be stored in association with a process (process ID). Each of the plurality of sets of frequency groups includes a plurality of frequency sets. The high-frequency power supply 31 may select a set of frequency groups for its pulse period from the plurality of sets of frequency groups corresponding to the specified process (process ID). The high-frequency power supply 31 may use the plurality of frequency sets included in the selected set of frequency groups in the ignition period P IG and all cycles included in the first period P1 within its pulse period, respectively. In this case, a plurality of conversion matrices A for each of the plurality of pulse periods PP1 to PP K are created. Each of the plurality of conversion matrices A may be a matrix including elements of (L×N) rows × Y rows. Here, "L" is the number of the plurality of frequency sets for that pulse period, and is the ignition period P within that pulse period IGand is the number of all cycles CY included in the first period P1. In this case, each of the output matrix O and the matrix F includes (L×N) rows × X rows of elements.

[0120] Here, various exemplary embodiments included in the present disclosure are described in [E1] to [E19] below.

[0121] [E1] a chamber, a substrate support portion provided in the chamber, a bias power supply that is electrically coupled to the substrate support portion and is configured to generate an electrical bias energy, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the bias power supply; a high-frequency power supply that is electrically connected to a high-frequency electrode and is configured to generate a source high-frequency power for generating plasma from a gas in the chamber; comprising the high-frequency power supply selects an initial frequency set obtained according to a specified process, in a first period, uses a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy, in a second period after the first period, adjusts the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce a power level of a reflected wave from a load of the source high-frequency power, is configured as a plasma processing apparatus.

[0122] [E2] When the high-frequency power supply includes a frequency set corresponding to the specified process among a plurality of frequency sets respectively corresponding to a plurality of processes, the high-frequency power supply is configured to select the frequency set corresponding to the specified process as the initial frequency set. The plasma processing apparatus according to E1.

[0123] [E3] The high-frequency power supply is configured to update the frequency set corresponding to the specified process with a frequency set including a plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods obtained by repeating the waveform period of the electrical bias energy in the second period. The plasma processing apparatus according to E2.

[0124] [E4] The plurality of process condition data sets for each of the plurality of processes and the plurality of frequency sets are associated with each other and registered in a database. The plasma processing apparatus according to E3.

[0125] [E5] The database is provided in a server that can be accessed by communication from the plasma processing apparatus or both the plasma processing apparatus and other plasma processing apparatuses. The plasma processing apparatus according to E4.

[0126] [E6] Each of the plurality of process condition data sets includes a plurality of condition items. The plasma processing apparatus according to E4 or E5.

[0127] [E7] A conversion matrix that minimizes the error between an output matrix obtained by multiplying the input matrix having the plurality of process condition data sets as a plurality of columns and a matrix having the plurality of frequency sets as a plurality of columns is registered in the database. The plasma processing apparatus according to E6.

[0128] [E8] When the frequency set corresponding to the specified process is updated, the conversion matrix is updated so as to minimize the error between the output matrix obtained by the product of the frequency set and the input matrix and a matrix having the plurality of frequency sets including the updated frequency set as a plurality of columns, the plasma processing apparatus according to E7.

[0129] [E9] When the frequency set corresponding to the specified process is not included in the plurality of frequency sets respectively corresponding to the plurality of processes, the plasma processing apparatus according to E7 or E8, configured to select, as the initial frequency set, a frequency set obtained by the product of the process condition data set of the specified process and the conversion matrix.

[0130] [E10] Each of the plurality of process condition data sets includes, as the plurality of condition items, at least one parameter of the pressure in the chamber, the power level of the source high-frequency power, the electrical bias energy, and the flow rate of each of one or more gases supplied into the chamber, the plasma processing apparatus according to any one of E6 to E9.

[0131] [E11] The electrical bias energy includes a bias high-frequency power having the bias frequency or a pulse of a voltage periodically generated at a time interval having a time length that is the reciprocal of the bias frequency. At least one parameter of the electrical bias energy includes type information indicating whether the electrical bias energy is the bias high-frequency power or the pulse of the voltage, the bias frequency, the power level of the bias high-frequency power, the duty ratio of the pulse of the voltage, and the voltage level of the pulse of the voltage, the plasma processing apparatus according to E10.

[0132] [E12] Further comprising a matcher including a matching circuit provided between the high-frequency power source and the high-frequency electrode. Each of the plurality of process condition data sets further includes, as the plurality of condition items, the capacitance of at least one variable capacitor of the matching circuit. The plasma processing apparatus described in E11.

[0133] [E13] The plasma processing apparatus is a capacitively coupled plasma processing apparatus. An upper electrode provided above the substrate support portion. A DC power source connected to the upper electrode. And further includes. Each of the plurality of process condition data sets further includes, as the plurality of condition items, the voltage level of the DC voltage applied from the DC power source to the upper electrode. The plasma processing apparatus according to E11 or E12.

[0134] [E14] The high-frequency power source is configured to use, as the source frequency of the source high-frequency power for the nth phase period within the mth waveform period of the electrical bias energy in the second period, the frequency obtained by giving a frequency shift so as to suppress the power level of the reflected wave to the source frequency of the source high-frequency power for the nth phase period within the waveform period of the electrical bias energy before the mth waveform period. The n is from 1 to N, and the N is the number of the plurality of phase periods within the waveform period of the electrical bias energy. The plasma processing apparatus according to any one of E1 to E13.

[0135] [E15] The high-frequency power source. In the nth phase period within the waveform period of the electrical bias energy in the second period, a plurality of candidate frequencies are sequentially used as the source frequency of the source high-frequency power. As the source frequency of the source high-frequency power for the nth phase period, a frequency that minimizes the power level of the reflected wave from the load of the source high-frequency power is selected from the plurality of candidate frequencies. configured as follows, wherein n is an integer from 1 to N, and N is the number of the plurality of phase periods within the waveform period of the electrical bias energy, The plasma processing apparatus according to any one of E1 to E13.

[0136] [E16] A bias power supply configured to generate electrical bias energy supplied to a substrate support provided in a chamber of a plasma processing apparatus, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the bias power supply, A high-frequency power supply configured to generate source high-frequency power supplied to a high-frequency electrode to generate plasma from a gas in the chamber, comprising, wherein the high-frequency power supply, selects an initial frequency set obtained according to a specified process, in a first period, uses a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy, in a second period after the first period, adjusts the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce a power level of a reflected wave from a load of the source high-frequency power, configured as follows, A power supply system.

[0137] [E17] (a) A step of supplying electrical bias energy having a bias frequency from a bias power supply to a substrate support provided in a chamber of a plasma processing apparatus, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the step, (b) A step of supplying source high-frequency power from a high-frequency power source to a high-frequency electrode to generate plasma from gas in the chamber; including; wherein (b) comprises a step of selecting an initial frequency set obtained according to a specified process; a step of using, as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within a waveform period of the electrical bias energy in a first period, a plurality of frequencies included in the initial frequency set; a step of adjusting, in a second period after the first period, the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce a power level of a reflected wave from a load of the source high-frequency power; including; a control method.

[0138] [E18] A program executed by a computer of the plasma processing apparatus so as to cause the plasma processing apparatus to execute the control method according to E17.

[0139] [E19] A storage medium storing the program according to E18.

[0140] From the above description, it will be understood that various embodiments of the present disclosure are described herein for purposes of illustration and that various changes can be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the appended claims.

Description of Reference Numerals

[0141] 1... Plasma processing apparatus, 10... Chamber, 11... Substrate support unit, 30... Power supply system, 31... High-frequency power source, 32... Bias power supply, 35... Sensor, 36... Sensor.

Claims

1. A chamber, a substrate support portion provided in the chamber, a bias power supply that is electrically coupled to the substrate support portion and is configured to generate an electrical bias energy, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the bias power supply; a high-frequency power supply that is electrically connected to a high-frequency electrode and is configured to generate a source high-frequency power for generating plasma from a gas in the chamber; comprising the high-frequency power supply is configured to generate the source high-frequency power in a first period and a second period after the first period, the bias power supply is configured to generate the electrical bias energy in the first period and the second period, the high-frequency power supply selects an initial frequency set obtained according to a specified process, in the first period, uses a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within a waveform period of the electrical bias energy, in the second period, adjusts the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce a power level of a reflected wave from a load of the source high-frequency power, is configured as a plasma processing apparatus.

2. The plasma processing apparatus according to claim 1, wherein the high-frequency power supply is configured to select, as the initial frequency set, the frequency set corresponding to the specified process when the frequency set corresponding to the specified process is included in a plurality of frequency sets respectively corresponding to a plurality of processes.

3. The plasma processing apparatus according to claim 2, wherein the high-frequency power supply is configured to update the frequency set corresponding to the specified process with a frequency set including a plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods obtained by repeating a waveform period of the electrical bias energy in the second period.

4. The plasma processing apparatus according to claim 3, wherein a plurality of process condition data sets for each of the plurality of processes and the plurality of frequency sets are associated with each other and registered in a database.

5. The plasma processing apparatus according to claim 4, wherein the database is provided in the plasma processing apparatus or a server accessible by communication from both the plasma processing apparatus and other plasma processing apparatuses.

6. The plasma processing apparatus according to claim 4, wherein each of the plurality of process condition data sets includes a plurality of condition items.

7. A conversion matrix that minimizes an error between an output matrix obtained by a product of the plurality of process condition data sets as a plurality of columns and an input matrix, and a matrix having the plurality of frequency sets as a plurality of columns is registered in the database. The plasma processing apparatus according to claim 6.

8. When the frequency set corresponding to the specified process is updated, the conversion matrix is updated so as to minimize an error between an output matrix obtained by a product of the frequency set and the input matrix, and a matrix having the updated plurality of frequency sets as a plurality of columns. The plasma processing apparatus according to claim 7.

9. When the frequency set corresponding to the specified process is not included in the plurality of frequency sets corresponding to the plurality of processes respectively, the high-frequency power supply is configured to select, as the initial frequency set, a frequency set obtained by a product of the process condition data set of the specified process and the conversion matrix. The plasma processing apparatus according to claim 7.

10. Each of the plurality of process condition data sets includes, as the plurality of condition items, at least one parameter of the pressure in the chamber, the power level of the source high-frequency power, the electrical bias energy, and the flow rate of each of one or more gases supplied into the chamber. The plasma processing apparatus according to claim 6.

11. The electrical bias energy includes a bias high-frequency power having the bias frequency or a pulse of a voltage periodically generated at time intervals having a time length that is the reciprocal of the bias frequency. At least one parameter of the electrical bias energy includes type information indicating whether the electrical bias energy is the bias high-frequency power or a pulse of the voltage, the bias frequency, the power level of the bias high-frequency power, the duty ratio of the pulse of the voltage, and the voltage level of the pulse of the voltage. The plasma processing apparatus according to claim 10.

12. The plasma processing apparatus further includes a matcher including a matching circuit provided between the high-frequency power supply and the high-frequency electrode. Each of the plurality of process condition data sets further includes, as the plurality of condition items, the capacitance of at least one variable capacitor of the matching circuit. The plasma processing apparatus according to claim 11.

13. The plasma processing apparatus is a capacitively coupled plasma processing apparatus. An upper electrode provided above the substrate support portion. A DC power supply connected to the upper electrode. The plasma processing apparatus further includes. Each of the plurality of process condition data sets further includes, as the plurality of condition items, the voltage level of the DC voltage applied from the DC power supply to the upper electrode. The plasma processing apparatus according to claim 11.

14. The high-frequency power supply is configured to use a frequency obtained by giving a frequency shift so as to suppress the power level of the reflected wave to the source frequency of the source high-frequency power for the nth phase period within the mth waveform period of the electrical bias energy in the second period, which is the source frequency of the source high-frequency power for the nth phase period within the waveform period of the electrical bias energy before the mth waveform period. The n is from 1 to N, and the N is the number of the plurality of phase periods within the waveform period of the electrical bias energy. The plasma processing apparatus according to any one of claims 1 to 13.

15. The high-frequency power supply is configured to: In the nth phase period within the waveform period of the electrical bias energy in the second period, sequentially use a plurality of candidate frequencies as the source frequency of the source high-frequency power. Select, as the source frequency of the source high-frequency power for the nth phase period, a frequency that minimizes the power level of the reflected wave from the load of the source high-frequency power among the plurality of candidate frequencies. The plasma processing apparatus is configured as such. The n is from 1 to N, and the N is the number of the plurality of phase periods within the waveform period of the electrical bias energy. The plasma processing apparatus according to any one of claims 1 to 13.

16. A bias power supply configured to generate electrical bias energy supplied to a substrate support provided in a chamber of a plasma processing apparatus, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the bias power supply, A high-frequency power supply configured to generate source high-frequency power supplied to a high-frequency electrode to generate plasma from a gas in the chamber, Comprising, The high-frequency power supply is configured to generate the source high-frequency power in a first period and a second period after the first period, The bias power supply is configured to generate the electrical bias energy in the first period and the second period, The high-frequency power supply, Selects an initial frequency set obtained according to a specified process, In the first period, uses a plurality of frequencies included in the initial frequency set as a plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within a waveform period of the electrical bias energy, In the second period, adjusts the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce a power level of a reflected wave from a load of the source high-frequency power, Is configured as, Power supply system.

17. (a) A step of supplying electrical bias energy having a bias frequency from a bias power supply to a substrate support provided in a chamber of a plasma processing apparatus, the electrical bias energy having a bias frequency, and a waveform period of the electrical bias energy having a time length that is the reciprocal of the bias frequency, the step, (b) A step of supplying source high-frequency power from a high-frequency power supply to a high-frequency electrode to generate plasma from a gas in the chamber, Including, The (b) includes the high-frequency power supply generating the source high-frequency power in a first period and a second period after the first period, The (a) includes the bias power supply generating the electrical bias energy in the first period and the second period, The (b) is, A step of selecting an initial frequency set obtained according to a specified process, In the first period, using a plurality of frequencies included in the initial frequency set as the plurality of source frequencies of the source high-frequency power for each of a plurality of phase periods within the waveform period of the electrical bias energy; In the second period, adjusting the plurality of source frequencies of the source high-frequency power for each of the plurality of phase periods within the waveform period of the electrical bias energy so as to reduce the power level of the reflected wave from the load of the source high-frequency power; including; A control method.

18. A program executed by a computer of the plasma processing apparatus so that the control method according to claim 17 is executed by the plasma processing apparatus.

19. A storage medium storing the program according to claim 18.

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