Plasma processing apparatus and control method

Abstract

The disclosed plasma processing apparatus includes a chamber, a substrate support, and an upper electrode. The substrate support is disposed in the chamber. The upper electrode has a plurality of gas holes and is provided above the substrate support. During the ON period, source high-frequency power is supplied from a high-frequency power source to the high-frequency electrode, and an electrical bias is supplied from a first bias power source to the substrate support. In a first period including the start point of the ON period, a negative voltage having a first absolute value of its voltage level is applied from a second bias power source to the upper electrode. In a second period after the first period within the ON period, a negative voltage having a second absolute value of its voltage level is applied from the second bias power source to the upper electrode. The first absolute value is smaller than the second absolute value.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing apparatus and a control method.

Background Art

[0002] A plasma processing apparatus is used in plasma processing of a substrate. A capacitively coupled plasma processing apparatus is known as a type of plasma processing apparatus. The capacitively coupled plasma processing apparatus includes a chamber, a substrate support, and an upper electrode. The substrate support is disposed in the chamber. The upper electrode is disposed above the substrate support. The plasma processing apparatus described in Patent Document 1 supplies source high-frequency power for plasma generation and bias high-frequency power for ion drawing to the substrate support in a pulsed manner, and applies a negative voltage to the upper electrode.

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 suppressing discharge in the upper electrode of a plasma processing apparatus.

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, an upper electrode, a high-frequency power source, a first bias power source, a second bias power source, and a control unit. The substrate support is disposed within the chamber. The upper electrode is disposed above the substrate support. A plurality of gas holes for introducing gas into the chamber are formed in the upper electrode. The high-frequency power source is electrically coupled to a high-frequency electrode that is either the substrate support or the upper electrode, and is configured to generate source high-frequency power for generating plasma from gas within the chamber. The first bias power source is electrically coupled to the substrate support, and is configured to generate an electrical bias for drawing ions within the chamber onto a substrate on the substrate support. The second bias power source is configured to apply a negative voltage to the upper electrode. The control unit controls the high-frequency power source to supply source high-frequency power to the high-frequency electrode during an ON period. The control unit controls the first bias power source to supply an electrical bias to the substrate support during the ON period. The control unit controls the second bias power source to apply a negative voltage having a first absolute value to the upper electrode during a first period including the start point of the ON period. The control unit controls the second bias power source to apply a negative voltage having a second absolute value to the upper electrode during a second period after the first period within the ON period. The first absolute value is smaller than the second absolute value.

Advantages of the Invention

[0006] According to one exemplary embodiment, a technique for suppressing discharge within the upper electrode of a plasma processing apparatus is provided.

Brief Description of the Drawings

[0007]

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DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] Hereinafter, a configuration example of a plasma processing system will be described. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0010] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Further, the plasma processing apparatus 1 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 within 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 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space. 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.

[0011] 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. Accordingly, 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.

[0012] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is 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. Also, at least one RF / DC electrode coupled to an RF (Radio Frequency) power supply 31 and / or a DC (Direct Current) power supply 32 described later may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Accordingly, the substrate support portion 11 includes at least one lower electrode.

[0013] 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.

[0014] Further, the substrate support portion 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 in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0015] 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. Note that the gas introduction portion may include, in addition to the shower head 13, one or more side gas injection portions (SGI) attached to one or more openings formed in the side wall 10a.

[0016] 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-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one process gas.

[0017] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Also, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0018] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0019] The second RF generation unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0020] Further, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and is configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generation unit 32b is connected to at least one upper electrode and is configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0021] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Accordingly, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive-polarity voltage pulses and one or more negative-polarity voltage pulses within one cycle. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0022] The exhaust system 40 can be connected, for example, to the gas outlet 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.

[0023] The control unit 2 processes computer-executable instructions for causing the plasma processing apparatus 1 to execute various processes described in the present disclosure. The 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 control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is realized by, for example, 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 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).

[0024] Hereinafter, reference will be made to FIG. 2. FIG. 2 is a diagram schematically showing a plasma processing apparatus according to one exemplary embodiment. As shown in FIG. 2, the plasma processing apparatus 1 includes the upper electrode 14 described above. In one embodiment, the upper electrode 14 includes a top plate 141 and a cooling plate 142.

[0025] The top plate 141 is in contact with the plasma processing space 10s and defines the plasma processing space 10s from above. The top plate 141 is formed of a conductive material. The top plate 141 is formed of, for example, silicon. The cooling plate 142 is provided on the top plate 141 and supports the top plate 141. The cooling plate 142 is configured by forming a dielectric film such as aluminum oxide on the surface of a base material formed of, for example, aluminum. The cooling plate 142 has a refrigerant flow path 142f formed therein. Refrigerant is supplied to the refrigerant flow path 142f from a chiller unit 60 provided outside the chamber 10. The refrigerant supplied to the refrigerant flow path 142f is returned to the chiller unit 60. The top plate 141 is cooled by supplying refrigerant to the refrigerant flow path 142f.

[0026] The cooling plate 142 provides a gas diffusion chamber 13b. The top plate 141 and the cooling plate 142 provide a plurality of gas holes which are the plurality of gas inlets 13c described above. The plurality of gas holes extend from the gas diffusion chamber 13b through the cooling plate 142 and the top plate 141 and open toward the plasma processing space 10s.

[0027] The plasma processing apparatus 1 includes a high-frequency power supply 50, a first bias power supply 51, and a second bias power supply 52. The high-frequency power supply 50 is a first RF generation unit 31a and is electrically coupled to a high-frequency electrode. The high-frequency electrode is either the lower electrode described above of the substrate support unit 11 or the upper electrode 14. The high-frequency power supply 50 is configured to generate source high-frequency power for generating plasma from gas in the chamber 10 as a source RF signal. The high-frequency power supply 50 is electrically connected to the high-frequency electrode via a matcher 50m. The matcher 50m includes a matching circuit for matching the impedance of the load of the high-frequency power supply 50 to the output impedance of the high-frequency power supply 50.

[0028] The first bias power supply 51 is electrically coupled to the substrate support portion 11 (for example, the lower electrode described above). The first bias power supply 51 is configured to generate an electrical bias EB for attracting ions in the plasma in the chamber 10 to the substrate W on the substrate support portion 11. The electrical bias EB has a bias frequency. The bias frequency has a frequency within the range of 100 kHz or more and 60 MHz or less. The bias frequency is, for example, 400 kHz.

[0029] The first bias power supply 51 may be the second RF generation unit 31b described above. In this case, the first bias power supply 51 is configured to generate a bias high-frequency power LF, which is the bias RF signal described above, as the electrical bias EB. In this case, the first bias power supply 51 is electrically connected to the substrate support portion 11 via a matching unit 51m. The matching unit 51m includes a matching circuit for matching the impedance of the load of the first bias power supply 51 to the output impedance of the first bias power supply 51. The bias high-frequency power LF is a power having a sinusoidal waveform with a bias frequency, as shown in FIG. 3(a), and is generated periodically. The waveform period CY of the bias high-frequency power LF has a time length that is the reciprocal of the bias frequency.

[0030] Alternatively, the first bias power supply 51 may include the first DC generation unit 32a described above. In this case, the first bias power supply 51 is configured to periodically generate a voltage pulse VP, which is the first DC signal described above, as the electrical bias EB. In this case, the plasma processing apparatus 1 may not have a matching unit 51m, and the first bias power supply 51 is electrically connected to the substrate support portion 11 (for example, the lower electrode) without passing through the matching unit 51m. The voltage pulse VP is generated periodically at time intervals of the waveform period CY, as shown in FIG. 3(b). In the example of FIG. 3(b), the voltage pulse VP is a pulse of a negative voltage or a negative DC voltage. However, as long as ions can be attracted from the plasma to the substrate W, the polarity of the voltage pulse VP is not limited to the negative polarity.

[0031] The second bias power supply 52 includes the above-described second DC generation unit 32b and is electrically coupled to the upper electrode 14. The second bias power supply 52 is configured to apply a negative voltage UEV to the upper electrode 14. The second bias power supply 52 may include a variable DC power supply.

[0032] Hereinafter, with reference to FIGS. 2 and 3, FIG. 4 will be referred to. FIG. 4 is a timing chart related to a plasma processing apparatus according to one exemplary embodiment. The control unit 2 controls the high-frequency power supply 50 so as to supply source high-frequency power HF to the high-frequency electrode during the ON period P ON In the ON period P ON The power level of the source high-frequency power HF in the ON period P is, for example, 1000 W or more.

[0033] Also, the control unit 2 controls the first bias power supply 51 so as to supply an electrical bias EB to the substrate support unit 11 (for example, the lower electrode) during the ON period P ON When the electrical bias EB is bias high-frequency power LF, the power level of the bias high-frequency power LF in the ON period P ON is, for example, 3000 W or more and 100000 W or less. When the electrical bias EB includes a voltage pulse VP, the voltage level of the voltage pulse VP in the ON period P ON is, for example, a level in the range between -3000 V and -10000 V.

[0034] As shown in FIG. 4, the control unit 2 controls the second bias power supply 52 so as to apply a negative voltage UEV having a voltage level V1 with a first absolute value |V1| to the upper electrode 14 in a first period P1 including the start point of the ON period P ON |V1| is, for example, greater than 0 V and 300 V or less. |V1| is, for example, 200 V. The first period P1 may have a time length that is 4 times or more the waveform period CY. Also, the first period P1 may have a time length that is 8 times or less or 10 times or less the waveform period CY. Note that the first period P1 may start at the start point of the ON period P ON and may start at the start point of the ON period P ONIt may start from a point before or immediately before the start time.

[0035] Also, the control unit 2, in the second period P2 after the first period P1 within the ON period P ON controls the second bias power supply 52 so as to apply a negative voltage UEV having a voltage level V2 with a second absolute value |V2| to the upper electrode 14. Note that the first absolute value |V1| is smaller than the second absolute value |V2|. |V2| is, for example, 100 V or more and 1000 V or less. |V2| is, for example, 500 V.

[0036] In one embodiment, the ON period P ON may appear alternately with the OFF period P OFF The control unit 2 controls the high-frequency power supply 50 and the first bias power supply 51 so as to stop the supply of the source high-frequency power HF and the supply of the electrical bias EB in the OFF period P OFF That is, in one embodiment, the high-frequency power supply 50 is controlled by the control unit 2 to periodically supply pulses of the source high-frequency power HF, and the first bias power supply 51 is controlled by the control unit 2 to periodically supply pulses of the electrical bias EB. The pulses of the source high-frequency power HF and the pulses of the electrical bias EB are periodically supplied, for example, at a pulse frequency of 1 kHz or more and 20 kHz or less. That is, the ON period P ON appears periodically at time intervals that are the reciprocal of the pulse frequency.

[0037] The control unit 2 may control the second bias power supply 52 so as to apply a negative voltage UEV to the upper electrode 14 in the OFF period P OFF The third absolute value |V3| of the voltage level V3 of the negative voltage UEV in the OFF period P OFF may be larger than the second absolute value |V2|. |V3| is, for example, 300 V or more and 1000 V or less. |V3| is, for example, 1000 V.

[0038] In such a plasma processing apparatus 1, in the ON period P ONA negative voltage UEV is applied to the upper electrode 14. As a result, the distance between the plasma and the upper electrode 14 increases, and an increase in the temperature of the upper electrode 14 is suppressed.

[0039] Also, a first absolute value |V1| of the voltage level of the negative voltage UEV in the first period P1 is smaller than a second absolute value |V2| of the voltage level of the negative voltage UEV in the second period P2. Therefore, an ON period P that may occur if the voltage level of the negative voltage UEV in the first period P1 is not small ON Abnormal discharge at a plurality of gas holes of the upper electrode 14 immediately after the start of is suppressed.

[0040] Also, during the OFF period P OFF Since a negative voltage UEV is also applied to the upper electrode 14, during the OFF period P OFF The upper electrode 14 is discharged.

[0041] Hereinafter, with reference to FIG. 5, a control method of a plasma processing apparatus according to one exemplary embodiment will be described. FIG. 5 is a flowchart of a control method of a plasma processing apparatus according to one exemplary embodiment. The control method shown in FIG. 5 (hereinafter referred to as "method MT") includes steps STa to STd.

[0042] Step STa is performed over the ON period P ON In step STa, in order to generate plasma from the gas in the chamber 10 of the plasma processing apparatus 1, source high-frequency power HF is supplied from the high-frequency power supply 50 to the high-frequency electrode.

[0043] Step STb is performed over the ON period P ON In step STb, in order to draw ions in the chamber 10 to the substrate W on the substrate support portion 11, an electrical bias EB is supplied from the first bias power supply 51 to the substrate support portion 11 (for example, the lower electrode).

[0044] The process STc is performed in the first period P1 described above. In the process STc, a negative voltage UEV having a voltage level V1 with a first absolute value |V1| is applied from the second bias power supply 52 to the upper electrode 14.

[0045] The process STd is performed in the second period P2 described above. In the process STd, a negative voltage UEV having a voltage level V2 with a second absolute value |V2| is applied from the second bias power supply 52 to the upper electrode 14. As described above, the first absolute value |V1| is smaller than the second absolute value |V2|.

[0046] In the method MT as well, the ON period P ON may be alternately repeated with the OFF period P OFF In this case, the method MT further includes the process STe, the process STf, and the process STJ.

[0047] The processes STe and STf are performed over the OFF period P OFF In the process STe, the supply of the source high-frequency power HF and the electrical bias EB is stopped. In the process STf, a negative voltage UEV is applied from the second bias power supply 52 to the upper electrode 14. The third absolute value |V3| of the voltage level V3 of the negative voltage UEV in the process STf may be larger than the second absolute value |V2| as described above.

[0048] In the process STJ, it is determined whether or not a stop condition is satisfied. The stop condition is satisfied, for example, when the number of repetitions of the processes STa to STf reaches a predetermined number. When it is determined in the process STJ that the stop condition is not satisfied, the processing from the process STa is repeated again. When it is determined in the process STJ that the stop condition is satisfied, the method MT ends.

[0049] Hereinafter, with reference to FIG. 6, a plasma processing apparatus according to another exemplary embodiment will be described. FIG. 6 is a diagram schematically showing a plasma processing apparatus according to another exemplary embodiment. Hereinafter, the plasma processing apparatus 1B shown in FIG. 6 will be described from the viewpoint of differences from the plasma processing apparatus 1.

[0050] The plasma processing apparatus 1B further includes a detector 70. The detector 70 is configured to obtain a detection signal that varies from its normal magnitude when there is a possibility of discharge in the upper electrode 14. The detection period of the detection signal may include the whole or a part of the ON period P ON The detection period of the detection signal, which is the ON period P ON A part of which may include the start point of the ON period P ON The detection period of the detection signal may further include at least a part of the OFF period P OFF The detection signal is input to the control unit 2.

[0051] The detection signal may be a signal representing the emission intensity at the gas hole for monitoring among the plurality of gas holes (i.e., the plurality of gas inlets 13c) of the upper electrode 14. In this case, the detector 70 includes an optical sensor 71s configured to measure the emission intensity (hereinafter referred to as "emission intensity") at the gas hole for monitoring. An optical fiber extends between the optical sensor 71s and the gas hole for monitoring, optically connecting the optical sensor 71s and the gas hole for monitoring.

[0052] Alternatively, the detection signal may be a signal representing the potential or current value of the upper electrode 14. In this case, the detector 70 includes an electrical sensor 72s configured to measure the potential or current value of the upper electrode 14. The electrical sensor 72s is electrically connected to the upper electrode 14.

[0053] In the plasma processing apparatus 1B, when it is determined from the detection signal that there is no possibility of discharge in the upper electrode 14, the control unit 2 executes the first control, and when it is determined from the detection signal that there is a possibility of discharge in the upper electrode 14, the control unit 2 executes the second control.

[0054] When the light emission intensity at the gas hole for monitoring, the potential of the upper electrode 14, or the current value at the upper electrode 14 is equal to or greater than a threshold value, the control unit 2 may determine that there is a possibility of discharge at the upper electrode 14 and execute second control. In other cases, the control unit 2 executes first control.

[0055] Alternatively, when the difference value between the light emission intensity at the gas hole for monitoring, the potential of the upper electrode 14, or the current value at the upper electrode 14 and the corresponding value during normal operation is equal to or greater than a threshold value, the control unit 2 may determine that there is a possibility of discharge at the upper electrode 14 and execute second control. In other cases, the control unit 2 executes first control.

[0056] As shown in FIG. 7, the first control executed by the control unit 2 includes controlling the second bias power supply 52 to apply a negative voltage UEV having the above-described second absolute value |V2| to the upper electrode 14 over the ON period P. ON This includes controlling the second bias power supply 52 to apply a negative voltage UEV having the above-described second absolute value |V2| to the upper electrode 14 over the ON period P.

[0057] As shown in FIG. 4, the second control executed by the control unit 2 includes controlling the second bias power supply 52 to apply a negative voltage UEV having the above-described first absolute value |V1| to the upper electrode 14 in the first period P1. Further, as shown in FIG. 4, the second control executed by the control unit 2 includes controlling the second bias power supply 52 to apply a negative voltage UEV having the above-described second absolute value |V2| to the upper electrode 14 in the second period P2.

[0058] According to such a plasma processing apparatus 1B, it is possible to control the voltage applied to the upper electrode 14 by the first control without performing the second control that is unnecessary when there is no possibility of discharge at the upper electrode 14.

[0059] Hereinafter, with reference to FIG. 8, a control method for a plasma processing apparatus according to another exemplary embodiment will be described. FIG. 8 is a flowchart of a control method for a plasma processing apparatus according to another exemplary embodiment. Hereinafter, the control method shown in FIG. 8 (hereinafter referred to as "method MTB") will be described from the perspective of differences from method MT.

[0060] Method MTB further includes step STJB. In step STJB, it is determined by the control unit 2 whether there is a possibility of discharge at the upper electrode 14 from the detection signal acquired by the detector 70. For the determination of the possibility of discharge at the upper electrode 14, refer to the above description regarding the plasma processing apparatus 1B.

[0061] In step STJB, if it is determined that there is no possibility of discharge at the upper electrode 14, the above-described first control is executed in step ST1. After step ST1, the process may move to step STe.

[0062] In step STJB, if it is determined that there is a possibility of discharge at the upper electrode 14, the above-described second control is executed in step ST2. The second control includes steps STc and STd of method MT. After step ST2, the process may move to step STe.

[0063] Although various exemplary embodiments have been described above, various additions, omissions, substitutions, and changes may be made without being limited to the above-described exemplary embodiments. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0064] Here, various exemplary embodiments included in the present disclosure are described in [E1] to [E18] below.

[0065] [E1] A chamber, A substrate support disposed in the chamber, An upper electrode disposed above the substrate support, and a plurality of gas holes for introducing gas into the chamber are formed in the upper electrode, A high-frequency power supply that is electrically coupled to the substrate support portion or the high-frequency electrode that is the upper electrode and is configured to generate source high-frequency power for generating plasma from gas in the chamber, A first bias power supply that is electrically coupled to the substrate support portion and is configured to generate an electrical bias for drawing ions in the chamber to a substrate on the substrate support portion, A second bias power supply configured to apply a negative voltage to the upper electrode, A control unit, Comprising, The control unit, Controls the high-frequency power supply to supply the source high-frequency power to the high-frequency electrode during the ON period, Controls the first bias power supply to supply the electrical bias to the substrate support portion during the ON period, Controls the second bias power supply to apply the negative voltage having a first absolute value to the upper electrode in a first period including the start point of the ON period, Controls the second bias power supply to apply the negative voltage having a second absolute value to the upper electrode in a second period after the first period within the ON period, Is configured as follows, The first absolute value is smaller than the second absolute value, A plasma processing apparatus.

[0066] [E2] The electrical bias is bias high-frequency power having a bias frequency or a voltage pulse periodically generated at a time interval that is the reciprocal of the bias frequency, The first period has a length that is 4 times or more the length of a period having a time length that is the reciprocal of the bias frequency from the start point, The plasma processing apparatus according to E1.

[0067] [E3] The plasma processing apparatus according to E2, wherein the first period has a length that is 8 times or less, or 10 times or less, of the period.

[0068] [E4] The ON period appears alternately with the OFF period, The control unit is configured to control the high-frequency power supply and the first bias power supply so as to stop the supply of the high-frequency power and the supply of the electrical bias during the OFF period. The plasma processing apparatus according to any one of E1 to E3.

[0069] [E5] The control unit is configured to control the second bias power supply so as to apply the negative voltage having a third absolute value whose voltage level is greater than the second absolute value to the upper electrode during the OFF period. The plasma processing apparatus according to E4.

[0070] [E6] The upper electrode is a top plate in contact with the plasma processing space in the chamber, a cooling plate provided on the top plate and having a refrigerant flow path therein, The plasma processing apparatus according to any one of E1 to E5, including

[0071] [E7] The top plate is formed of silicon. The plasma processing apparatus according to E6.

[0072] [E8] A step of supplying source high-frequency power from a high-frequency power supply to a high-frequency electrode, which is a substrate support in the chamber or an upper electrode disposed above the substrate support, in order to generate plasma from the gas in the chamber of the plasma processing apparatus during the ON period; A step of supplying an electrical bias from a first bias power supply to the substrate support in order to draw ions in the chamber onto the substrate on the substrate support during the ON period; In a first period including the start point of the ON period, applying a negative voltage having a first absolute value from a second bias power supply to the upper electrode; In a second period after the first period within the ON period, applying the negative voltage having a second absolute value from the second bias power supply to the upper electrode; including; wherein the first absolute value is smaller than the second absolute value; Control method.

[0073] [E9] a chamber; a substrate support disposed within the chamber; an upper electrode disposed above the substrate support, the upper electrode having a plurality of gas holes for introducing gas into the chamber; a high-frequency power supply electrically coupled to the high-frequency electrode that is the substrate support or the upper electrode, and configured to generate source high-frequency power for generating plasma from gas within the chamber; a first bias power supply electrically coupled to the substrate support and configured to generate an electrical bias for drawing ions within the chamber to a substrate on the substrate support; a second bias power supply configured to apply a negative voltage to the upper electrode; a detector configured to acquire a detection signal that is a signal representing the emission intensity at a monitoring gas hole among the plurality of gas holes or a signal representing the potential or current value of the upper electrode; a control unit; comprising; wherein the control unit controls the high-frequency power supply to supply the source high-frequency power to the high-frequency electrode during the ON period; controls the first bias power supply to supply the electrical bias to the substrate support during the ON period; when it is determined from the detection signal that there is no possibility of discharge at the upper electrode, executes first control; When it is determined from the detection signal that there is a possibility of discharge at the upper electrode, execute a second control. It is configured as follows. The second control includes controlling the second bias power supply so as to apply the negative voltage having the first absolute value to the upper electrode in a first period including the start point of the ON period; controlling the second bias power supply so as to apply the negative voltage having the second absolute value to the upper electrode in a second period after the first period within the ON period; including The first control includes controlling the second bias power supply so as to apply the negative voltage having the second absolute value to the upper electrode over the ON period. The first absolute value is smaller than the second absolute value. A plasma processing apparatus.

[0074] [E10] The electrical bias is bias high-frequency power having a bias frequency or a voltage pulse periodically generated at a time interval that is the reciprocal of the bias frequency. The first period has a length that is 4 times or more the length of a period having a time length that is the reciprocal of the bias frequency from the start point. The plasma processing apparatus according to E9.

[0075] [E11] The plasma processing apparatus according to E10, wherein the first period has a length that is 8 times or less or 10 times or less the length of the period.

[0076] [E12] The ON period appears alternately with the OFF period. The control unit is configured to control the high-frequency power supply and the first bias power supply so as to stop the supply of the high-frequency power and the supply of the electrical bias in the OFF period. The plasma processing apparatus according to any one of E9 to E11.

[0077] [E13] The control unit is configured to control the second bias power supply so as to apply the negative voltage having a third absolute value whose voltage level is greater than the second absolute value to the upper electrode during the OFF period, the plasma processing apparatus according to E12.

[0078] [E14] The upper electrode is a top plate in contact with the plasma processing space in the chamber, a cooling plate having a refrigerant flow path therein and provided on the top plate, and includes the plasma processing apparatus according to any one of E9 to E13.

[0079] [E15] The top plate is formed of silicon, the plasma processing apparatus according to E14.

[0080] [E16] The control unit is configured to execute the second control when the light emission intensity, the potential, or the current value specified from the detection signal is equal to or greater than a threshold value, the plasma processing apparatus according to any one of E9 to E15.

[0081] [E17] The control unit is configured to execute the second control when a difference value between the light emission intensity, the potential, or the current value specified from the detection signal and a normal value of the light emission intensity, the potential, or the current value is equal to or greater than a threshold value, the plasma processing apparatus according to any one of E9 to E15.

[0082] [E18] In order to generate plasma from the gas in the chamber of the plasma processing apparatus during the ON period, a step of supplying source high-frequency power from a high-frequency power supply to a high-frequency electrode which is a substrate support portion in the chamber or an upper electrode disposed above the substrate support portion; During the ON period, a step of supplying an electrical bias from a first bias power supply to the substrate support to draw ions in the chamber into the substrate on the substrate support; When it is determined from a detection signal, which is a signal representing the emission intensity at a gas hole for monitoring among a plurality of gas holes of the upper electrode for introducing gas into the chamber, or a signal representing the potential or current value of the upper electrode, that there is no possibility of discharge at the upper electrode, a step of executing first control; When it is determined from the detection signal that there is a possibility of discharge at the upper electrode, a step of executing second control; including The second control includes a step of applying, from a second bias power supply to the upper electrode, a negative voltage having a first absolute value of its voltage level in a first period including the start point of the ON period; a step of applying, from the second bias power supply to the upper electrode, the negative voltage having a second absolute value of its voltage level in a second period after the first period within the ON period; including The first control includes applying, across the ON period, from the second bias power supply to the upper electrode, the negative voltage having the second absolute value of its voltage level; The first absolute value is smaller than the second absolute value. Control method.

[0083] From the above description, it will be understood that the 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.

Explanation of Reference Numerals

[0084] 1... Plasma processing apparatus, 2... Control unit, 10... Chamber, 11... Substrate support, 14... Upper electrode, 50... High-frequency power supply, 51... First bias power supply, 52... Second bias power supply.

Claims

1. A chamber; a substrate support disposed within the chamber; an upper electrode disposed above the substrate support, the upper electrode having a plurality of gas holes formed therein for introducing gas into the chamber; a radio frequency power source electrically coupled to the substrate support or the upper electrode, the radio frequency electrode, and configured to generate a source radio frequency power for generating a plasma from a gas in the chamber; a first bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions in the chamber to a substrate on the substrate support; a second bias power supply configured to apply a negative voltage to the upper electrode; A control unit; Equipped with The control unit is controlling the high frequency power source so as to supply the source high frequency power to the high frequency electrode during an ON period; controlling the first bias power supply to supply the electric bias to the substrate support during the ON period; controlling the second bias power supply to apply the negative voltage, the voltage level of which has a first absolute value, to the upper electrode during a first period including a start point of the ON period; controlling the second bias power supply to apply the negative voltage, the voltage level of which has a second absolute value, to the upper electrode during a second period after the first period in the ON period; It is structured as follows: the first absolute value is less than the second absolute value; Plasma processing equipment.

2. The electrical bias is a high-frequency bias power having a bias frequency or a voltage pulse periodically generated at a time interval of the reciprocal of the bias frequency; The first period has a length equal to or greater than four times a period having a time length equal to the reciprocal of the bias frequency from the start point in time. The plasma processing apparatus according to claim 1 .

3. The plasma processing apparatus of claim 2 , wherein the first period has a length equal to or less than eight or ten times the length of the period.

4. The ON periods alternate with OFF periods, The control unit is configured to control the high frequency power supply and the first bias power supply so as to stop the supply of the high frequency power and the supply of the electric bias during the OFF period. The plasma processing apparatus according to any one of claims 1 to 3.

5. 5. The plasma processing apparatus according to claim 4, wherein the control unit is configured to control the second bias power supply so as to apply the negative voltage, the voltage level of which has a third absolute value greater than the second absolute value, to the upper electrode during the OFF period.

6. The upper electrode is a top plate in contact with a plasma processing space in the chamber; a cooling plate having a refrigerant flow path therein and provided on the top plate; The plasma processing apparatus according to any one of claims 1 to 3, comprising:

7. The plasma processing apparatus according to claim 6 , wherein the top plate is made of silicon.

8. supplying a source high frequency power from a high frequency power source to a high frequency electrode, which is a substrate support part in the chamber or an upper electrode arranged above the substrate support part, in order to generate plasma from a gas in the chamber of the plasma processing apparatus during an ON period; supplying an electrical bias from a first bias power supply to the substrate support during the ON period to attract ions in the chamber to a substrate on the substrate support; applying a negative voltage having a first absolute value from a second bias power supply to the upper electrode during a first period including a start point of the ON period; applying the negative voltage, the voltage level of which has a second absolute value, from the second bias power supply to the upper electrode during a second period following the first period in the ON period; Including, the first absolute value is less than the second absolute value; Control methods.

9. A chamber; a substrate support disposed within the chamber; an upper electrode disposed above the substrate support, the upper electrode having a plurality of gas holes formed therein for introducing gas into the chamber; a radio frequency power source electrically coupled to the substrate support or the upper electrode, the radio frequency electrode, and configured to generate a source radio frequency power for generating a plasma from a gas in the chamber; a first bias power supply electrically coupled to the substrate support and configured to generate an electrical bias to attract ions in the chamber to a substrate on the substrate support; a second bias power supply configured to apply a negative voltage to the upper electrode; a detector configured to obtain a detection signal which is a signal representing an emission intensity at a monitor gas hole among the plurality of gas holes or a signal representing a potential or a current value of the upper electrode; A control unit; Equipped with The control unit is controlling the high frequency power source so as to supply the source high frequency power to the high frequency electrode during an ON period; controlling the first bias power supply to supply the electric bias to the substrate support during the ON period; executing a first control when it is determined from the detection signal that there is no possibility of discharge at the upper electrode; executing a second control when it is determined from the detection signal that there is a possibility of discharge in the upper electrode; It is structured as follows: The second control is controlling the second bias power supply to apply the negative voltage, the voltage level of which has a first absolute value, to the upper electrode during a first period including a start point of the ON period; controlling the second bias power supply to apply the negative voltage, the voltage level of which has a second absolute value, to the upper electrode during a second period after the first period in the ON period; Including, the first control includes controlling the second bias power supply to apply the negative voltage, the voltage level of which has the second absolute value, to the upper electrode during the ON period; the first absolute value is less than the second absolute value; Plasma processing equipment.

10. The electrical bias is a high-frequency bias power having a bias frequency or a voltage pulse periodically generated at a time interval of the reciprocal of the bias frequency; The first period has a length equal to or greater than four times a period having a time length equal to the reciprocal of the bias frequency from the start point in time. The plasma processing apparatus according to claim 9 .

11. The plasma processing apparatus of claim 10 , wherein the first period has a length equal to or less than eight or ten times the length of the period.

12. The ON periods alternate with OFF periods, The control unit is configured to control the high frequency power supply and the first bias power supply so as to stop the supply of the high frequency power and the supply of the electric bias during the OFF period. The plasma processing apparatus according to any one of claims 9 to 11.

13. 13. The plasma processing apparatus of claim 12, wherein the control unit is configured to control the second bias power supply so as to apply the negative voltage, the voltage level of which has a third absolute value greater than the second absolute value, to the upper electrode during the OFF period.

14. The upper electrode is a top plate in contact with a plasma processing space in the chamber; a cooling plate having a refrigerant flow path therein and provided on the top plate; The plasma processing apparatus according to any one of claims 9 to 11, comprising:

15. The plasma processing apparatus according to claim 14 , wherein the top plate is made of silicon.

16. The plasma processing apparatus according to any one of claims 9 to 11, wherein the control unit is configured to execute the second control when the emission intensity, the potential, or the current value identified from the detection signal is greater than or equal to a threshold value.

17. The plasma processing apparatus of any one of claims 9 to 11, wherein the control unit is configured to execute the second control when a difference value between the emission intensity, the potential, or the current value identified from the detection signal and a normal value of the emission intensity, the potential, or the current value is greater than or equal to a threshold value.

18. supplying a source high frequency power from a high frequency power source to a high frequency electrode, which is a substrate support part in the chamber or an upper electrode arranged above the substrate support part, in order to generate plasma from a gas in the chamber of the plasma processing apparatus during an ON period; supplying an electrical bias from a first bias power supply to the substrate support during the ON period to attract ions in the chamber to a substrate on the substrate support; executing a first control when it is determined that there is no possibility of discharge in the upper electrode from a detection signal which is a signal representing an emission intensity in a monitor gas hole among a plurality of gas holes in the upper electrode for introducing gas into the chamber or a signal representing a potential or a current value of the upper electrode; executing a second control when it is determined from the detection signal that there is a possibility of discharge in the upper electrode; Including, The second control is applying a negative voltage having a first absolute value from a second bias power supply to the upper electrode during a first period including a start point of the ON period; applying the negative voltage, the voltage level of which has a second absolute value, from the second bias power supply to the upper electrode during a second period following the first period in the ON period; Including, the first control includes applying the negative voltage, the voltage level of which has the second absolute value, from the second bias power supply to the upper electrode during the ON period; the first absolute value is less than the second absolute value; Control methods.

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