Plasma treatment apparatus and control method for plasma treatment apparatus

Abstract

The plasma processing apparatus disclosed in this invention includes a chamber, a substrate support, and an upper electrode. The substrate support is disposed within the chamber. The upper electrode has a plurality of vents and is disposed above the substrate support. During the on-time, source high-frequency power is supplied to the high-frequency electrode from a high-frequency power supply, and an electrical bias voltage is supplied to the substrate support from a first bias power supply. During the first period, including the start point of the on-time, a negative voltage with a first absolute value is applied to the upper electrode from a second bias power supply. During the second period following the first period within the on-time, a negative voltage with a second absolute value is applied to the upper electrode from the second bias power supply. The first absolute value is less than the second absolute value.

Description

Technical Field

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

[0002] Plasma processing devices are used for plasma processing of substrates. Capacitively coupled plasma processing devices are well known as one type of plasma processing device. These devices include a chamber, a substrate support, and an upper electrode. The substrate support is disposed within the chamber. The upper electrode is disposed above the substrate support. The plasma processing device described in Patent Document 1 supplies pulsed high-frequency source power for plasma generation and high-frequency bias power for ion injection to the substrate support, while applying a negative voltage to the upper electrode. Prior Art Literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-171320 Summary of the Invention

[0004] [Problems to be solved by the invention] The present invention provides a technology for suppressing discharge in an upper electrode of a plasma processing device. [Technical means to solve the problem]

[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 supply, a first bias power supply, a second bias power supply, and a control unit. The substrate support is disposed within the chamber. The upper electrode is disposed above the substrate support. The upper electrode is formed with a plurality of gas holes for introducing gas into the chamber. The high-frequency power supply is electrically coupled to a high-frequency electrode, which is either the substrate support or the upper electrode, and is configured to generate source high-frequency power within the chamber for generating plasma from the gas. The first bias power supply is electrically coupled to the substrate support and is configured to generate an electrical bias for feeding ions within the chamber onto a substrate on the substrate support. The second bias power supply is configured to apply a negative voltage to the upper electrode. The control unit controls the high-frequency power supply to supply the source high-frequency power to the high-frequency electrode during an on-state period. The control unit controls the first bias power supply to supply an electrical bias to the substrate support during the on-state period. The control unit controls the second bias power supply to apply a negative voltage having a first absolute value to the upper electrode during a first period including the start time of the on period. The control unit controls the second bias power supply to apply a negative voltage having a second absolute value to the upper electrode during a second period following the first period within the on period. The first absolute value is smaller than the second absolute value. [Effects of the Invention]

[0006] According to an exemplary embodiment, a technique for suppressing discharge within an upper electrode of a plasma processing apparatus is provided. Simple diagram description

[0007] FIG. 1 is a diagram for explaining an example of the structure of a capacitively coupled plasma processing apparatus. FIG. 2 is a diagram schematically showing a plasma processing apparatus according to an exemplary embodiment. FIG3(a) and FIG3(b) are diagrams showing examples of waveforms of electrical bias voltages. FIG. 4 is a timing diagram associated with a plasma processing apparatus according to an exemplary embodiment. FIG5 is a flow chart of a method for controlling a plasma processing apparatus according to an exemplary embodiment. FIG6 is a diagram schematically showing a plasma processing apparatus according to another exemplary embodiment. FIG. 7 is a timing diagram related to a plasma processing apparatus according to another exemplary embodiment. FIG8 is a flow chart of a method for controlling a plasma processing apparatus according to another exemplary embodiment. Implementation Method

[0008] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0009] The following describes an example of the configuration of a plasma processing system. FIG1 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus.

[0010] A 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. Furthermore, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet 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 portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, sidewalls 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 into the plasma processing space 10s and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The shower head 13 and substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0011] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. In a top view, the annular region 111b of the main body 111 surrounds the central region 111a of the main body 111. The substrate W is placed on the central region 111a of the main body 111, and the ring assembly 112 is placed 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 the substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as the annular 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. Alternatively, another member 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 on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to the RF (Radio Frequency) power source 31 and / or DC (Direct Current) power source 32 described below can 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 DC signal is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Furthermore, the conductive member of the base 1110 and the at least one RF / DC electrode can function as a plurality of lower electrodes. Furthermore, the electrostatic electrode 1111b can function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0013] The ring assembly 112 includes one or more ring-shaped components. In one embodiment, the one or more ring-shaped components 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] Furthermore, 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 salt water 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. Furthermore, the substrate support portion 11 may include a heat transfer gas supply unit configured to supply heat transfer gas to the 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 processing 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 inlet ports 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the plurality of gas inlet ports 13c through the gas diffusion chamber 13b. The shower head 13 also includes at least one upper electrode. Furthermore, in addition to the shower head 13, the gas inlet unit may also include one or more side gas injectors (SGIs), which are installed in 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 each corresponding gas source 21 to the showerhead 13 via each corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation elements for modulating or pulsing the flow of the 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. This generates plasma from at least one process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a portion of a plasma generating unit configured to generate plasma from one or more process gases in the plasma processing chamber 10. Furthermore, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated in the substrate W, thereby feeding ions from the generated plasma into the substrate W.

[0018] In one embodiment, the RF power source 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is configured to generate a source RF signal (source RF power) for plasma generation, coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generator 31a may also 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 generator 31b is configured to generate a bias RF signal (bias RF power) coupled to at least one lower electrode via at least one impedance matching circuit. The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency within a range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may also be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0020] Furthermore, 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 generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0021] In various embodiments, at least one of the first and second DC signals can 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 can have a rectangular, trapezoidal, triangular, or a combination thereof pulse waveform. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and the at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute the voltage pulse generator. When the second DC generator 32b and the waveform generator constitute the voltage pulse generator, the voltage pulse generator is connected to the at least one upper electrode. The voltage pulses can have either positive or negative polarity. Furthermore, the sequence of voltage pulses can include one or more positive voltage pulses and one or more negative voltage pulses within a cycle. Furthermore, in addition to the RF power supply 31, the first and second DC generators 32a and 32b may be provided, and the first DC generator 32a may be provided instead of the second RF generator 31b.

[0022] The exhaust system 40 can be connected to, for example, a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure within the plasma processing space 10s. The vacuum pump can include a turbomolecular pump, a dry vacuum pump, or a combination thereof.

[0023] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various steps described herein. The control unit 2 can be configured to control the various components of the plasma processing apparatus 1 to perform the various steps described herein. In one embodiment, a portion or all of the control unit 2 can be included in the plasma processing apparatus 1. The control unit 2 can include a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The control unit 2 can be implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to read a program from the memory unit 2a2 and execute the read program to perform various control operations. The program can be pre-stored in the memory unit 2a2 or retrieved from a medium when necessary. The retrieved program is stored in the memory unit 2a2 and is retrieved and executed by the processing unit 2a1 from the memory unit 2a2. The medium can be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 can be a CPU (Central Processing Unit). The memory unit 2a2 can include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0024] 2 , which schematically illustrates a plasma processing apparatus according to an exemplary embodiment. As shown in FIG2 , 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 connected to the plasma processing space 10s and divides the plasma processing space 10s from above. The top plate 141 is formed of a conductive material. The top plate 141 is formed of silicon, for example. The cooling plate 142 is disposed on the top plate 141 and supports the top plate 141. The cooling plate 142 is formed by forming a dielectric film such as aluminum oxide on the surface of a base material formed of aluminum, for example. The cooling plate 142 has a coolant flow path 142f formed therein. The coolant flow path 142f is supplied with coolant from a cooler unit 60 disposed outside the chamber 10. The coolant supplied to the coolant flow path 142f returns to the cooler unit 60. The top plate 141 is cooled by supplying coolant to the coolant 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 that serve as the plurality of gas inlet ports 13c. 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 the first RF generator 31a and is electrically coupled to a high-frequency electrode. The high-frequency electrode is the lower electrode of the substrate support 11 or the upper electrode 14. The high-frequency power supply 50 is configured to generate a source high-frequency power as a source RF signal within the chamber 10 for generating plasma from a gas. The high-frequency power supply 50 is electrically connected to the high-frequency electrode via a matching device 50m. The matching device 50m includes a matching circuit for matching the impedance of the load of the high-frequency power supply 50 with the output impedance of the high-frequency power supply 50.

[0028] The first bias power supply 51 is electrically coupled to the substrate support 11 (e.g., the lower electrode described above). The first bias power supply 51 is configured to generate an electrical bias EB for feeding ions from the plasma within the chamber 10 onto the substrate W on the substrate support 11. The electrical bias EB has a bias frequency. The bias frequency is within a range of 100 kHz to 60 MHz. For example, the bias frequency is 400 kHz.

[0029] The first bias power supply 51 can be the second RF generator 31b described above. In this case, the first bias power supply 51 is configured to generate bias high-frequency power LF as the electrical bias voltage EB. This bias high-frequency power LF is the bias RF signal described above. In this case, the first bias power supply 51 is electrically connected to the substrate support 11 via a matching device 51m. The matching device 51m includes a matching circuit that matches the impedance of the load of the first bias power supply 51 with the output impedance of the first bias power supply 51. As shown in Figure 3(a), the bias high-frequency power LF is a power having a sinusoidal waveform having a bias frequency and is generated periodically. The waveform period CY of the bias high-frequency power LF has a duration equal to the inverse of the bias frequency.

[0030] Alternatively, the first bias power supply 51 may include the first DC generator 32a. In this case, the first bias power supply 51 is configured to periodically generate a voltage pulse VP as the electrical bias EB. This voltage pulse VP is the first DC signal. In this case, the plasma processing apparatus 1 may not include the matching element 51m; the first bias power supply 51 is electrically connected to the substrate support 11 (e.g., the lower electrode) without the matching element 51m. As shown in FIG3(b), the voltage pulse VP is periodically generated at intervals of the waveform period CY. Furthermore, in the example of FIG3(b), the voltage pulse VP is a negative voltage or negative DC voltage pulse. However, the polarity of the voltage pulse VP is not limited to negative polarity as long as ions can be fed from the plasma into the substrate W.

[0031] The second bias power supply 52 includes the second DC generator 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] 2, 3, and 4. FIG4 is a timing diagram related to a plasma processing apparatus according to an exemplary embodiment. The control unit 2 controls the high-frequency power source 50 to supply source high-frequency power HF to the high-frequency electrode during the on-period P ON. The power level of the source high-frequency power HF during the on-period P ON is, for example, 1000 W or greater.

[0033] Furthermore, the control unit 2 controls the first bias power supply 51 to supply an electrical bias voltage EB to the substrate support portion 11 (e.g., the lower electrode) during the on-period P ON. When the electrical bias voltage EB is a bias high-frequency power LF, the power level of the bias high-frequency power LF during the on-period P ON is, for example, greater than 3000 W and less than 100,000 W. When the electrical bias voltage EB includes a voltage pulse VP, the voltage level of the voltage pulse VP during the on-period P ON is, for example, within a range between -3000 V and -10,000 V.

[0034] As shown in FIG4 , the control unit 2 controls the second bias power supply 52 to apply a negative voltage UEV having a voltage level V1 having a first absolute value |V1| to the upper electrode 14 during a first period P1, which includes the start of the on-period PON. |V1| is, for example, greater than 0 V and less than 300 V. |V1| is, for example, 200 V. The first period P1 can have a duration of at least four times the waveform period CY. Alternatively, the first period P1 can have a duration of less than eight times or less than ten times the waveform period CY. Furthermore, the first period P1 can begin at the start of the on-period PON, or can begin before or immediately before the start of the on-period PON.

[0035] Furthermore, the control unit 2 controls the second bias power supply 52 to apply a negative voltage UEV having a second absolute value |V2| at its voltage level V2 to the upper electrode 14 during a second period P2 following the first period P1 within the on-period PON. Furthermore, the first absolute value |V1| is smaller than the second absolute value |V2|. For example, |V2| is between 100 V and 1000 V. For example, |V2| is 500 V.

[0036] In one embodiment, the on-period P ON may alternate with the off-period P OFF . The control unit 2 controls the high-frequency power supply 50 and the first bias power supply 51 to stop supplying the source high-frequency power HF and the electrical bias EB during the off-period P OFF . Specifically, 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 electrical bias EB are periodically supplied at a pulse frequency of, for example, 1 kHz to 20 kHz. That is, the on-period P ON periodically occurs at intervals equal to the inverse of the pulse frequency.

[0037] The control unit 2 can also control the second bias power supply 52 to apply a negative voltage UEV to the upper electrode 14 during the off period POFF. The third absolute value |V3| of the voltage level V3 of the negative voltage UEV during the off period POFF can be greater than the second absolute value |V2|. |V3| is, for example, not less than 300 V and not more than 1000 V. |V3| is, for example, 1000 V.

[0038] In the plasma processing apparatus 1, during the on period P ON, a negative voltage UEV is applied to the upper electrode 14. This increases the distance between the plasma and the upper electrode 14, thereby suppressing the temperature rise of the upper electrode 14.

[0039] Furthermore, the first absolute value |V1| of the voltage level of the negative voltage UEV during the first period P1 is smaller than the second absolute value |V2| of the voltage level of the negative voltage UEV during the second period P2. Therefore, abnormal discharges in the plurality of pores of the upper electrode 14 immediately after the start of the on-period PON, which might otherwise occur if the voltage level of the negative voltage UEV during the first period P1 were not small, are suppressed.

[0040] Furthermore, since the negative voltage UEV is also applied to the upper electrode 14 during the off period P OFF , the upper electrode 14 is de-staticized during the off period P OFF .

[0041] A control method for a plasma processing apparatus according to an exemplary embodiment will be described below with reference to FIG5 . FIG5 is a flow chart of a control method for a plasma processing apparatus according to an exemplary embodiment. The control method shown in FIG5 (hereinafter referred to as "method MT") includes steps STa through STd.

[0042] Step STa is performed during the entire 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 during the entire on period P ON. In step STb, in order to feed ions in the chamber 10 to the substrate W on the substrate support 11, an electric bias EB is supplied from the first bias power supply 51 to the substrate support 11 (eg, the lower electrode).

[0044] Step STc is performed during the first period P 1. In step STc, a negative voltage UEV having a first absolute value |V 1| at a voltage level V 1 is applied to the upper electrode 14 from the second bias power supply 52.

[0045] Step STd is performed during the second period P2. In step STd, a negative voltage UEV having a second absolute value |V2| at a voltage level 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 method MT, the on period P ON and the off period P OFF may be repeated alternately. In this case, method MT further includes step STe, step STf, and step STJ.

[0047] Steps STe and STf are performed throughout the off period P OFF. In step STe, the supply of source high-frequency power HF and electrical bias EB is stopped. In step STf, a negative voltage UEV is applied to the upper electrode 14 from the second bias power supply 52. ​​As described above, the third absolute value |V 3| of the voltage level V 3 of the negative voltage UEV in step STf can be greater than the second absolute value |V 2|.

[0048] In step STJ, a determination is made as to whether a stopping condition is satisfied. For example, the stopping condition is satisfied when steps STa through STf are repeated a specified number of times. If the stopping condition is determined not to be satisfied in step STJ, the process from step STa onward is repeated again. If the stopping condition is determined to be satisfied in step STJ, method MT terminates.

[0049] Another exemplary embodiment of a plasma processing apparatus will be described below with reference to FIG6 . FIG6 schematically illustrates another exemplary embodiment of a plasma processing apparatus. The following describes the plasma processing apparatus 1B shown in FIG6 from the perspective of its 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 a potential discharge exists in the upper electrode 14. The detection period of the detection signal may include all or a portion of the on-period P ON. The portion of the on-period P ON as the detection period of the detection signal may include the start time of the on-period P ON. The detection period of the detection signal may further include at least a portion 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 luminescence intensity within the monitoring pores of the plurality of pores (i.e., the plurality of gas inlet ports 13c) of the upper electrode 14. In this case, the detector 70 includes an optical sensor 71s configured to measure the intensity of luminescence within the monitoring pores (hereinafter referred to as "luminescence intensity"). An optical fiber extends between the optical sensor 71s and the monitoring pores, optically connecting the optical sensor 71s to the monitoring pores.

[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, the control unit 2 performs the first control when it is determined based on the detection signal that there is no possibility of discharge in the upper electrode 14, and performs the second control when it is determined based on the detection signal that there is a possibility of discharge in the upper electrode 14.

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

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

[0056] The first control performed by the control unit 2 includes: as shown in FIG7 , controlling the second bias power supply 52 to apply a negative voltage UEV having a voltage level V2 having the second absolute value |V2| to the upper electrode 14 during the entire on-period PON.

[0057] The second control performed by the control unit 2 includes, as shown in FIG4 , controlling the second bias power supply 52 to apply a negative voltage UEV having a voltage level V1 with the first absolute value |V1| to the upper electrode 14 during the first period P1. Furthermore, the second control performed by the control unit 2 includes, as shown in FIG4 , controlling the second bias power supply 52 to apply a negative voltage UEV having a voltage level V2 with the second absolute value |V2| to the upper electrode 14 during the second period P2.

[0058] According to the plasma processing apparatus 1B, when there is no possibility of discharge in the upper electrode 14, the voltage to be applied to the upper electrode 14 can be controlled by the first control without performing the unnecessary second control.

[0059] Referring to FIG8 , another exemplary embodiment of a method for controlling a plasma processing apparatus will be described below. FIG8 is a flow chart of another exemplary embodiment of a method for controlling a plasma processing apparatus. The control method shown in FIG8 (hereinafter referred to as "Method MTB") will be described below from the perspective of its differences from Method MT.

[0060] Method MTB further includes step STJB. In step STJB, control unit 2 determines whether there is a possibility of discharge in upper electrode 14 based on the detection signal obtained by detector 70. Regarding the determination of the possibility of discharge in upper electrode 14, please refer to the above description related to plasma processing apparatus 1B.

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

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

[0063] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements from different embodiments may be combined to form other embodiments.

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

[0065] [E1] A plasma processing device comprising: chamber; A substrate support portion, which is disposed in the chamber; An upper electrode is disposed above the substrate support portion and is formed with a plurality of gas holes for introducing gas into the chamber; a high-frequency power supply electrically coupled to the high-frequency electrode serving as the substrate support or the upper electrode, and configured to generate source high-frequency power for generating plasma from the gas within the chamber; a first bias power supply electrically coupled to the substrate support portion and configured to generate an electrical bias for feeding ions in the chamber to the substrate on the substrate support portion; a second bias power supply configured to apply a negative voltage to the upper electrode; and Control Department; The control unit is composed of: Controlling the high frequency power supply to supply the source high frequency power to the high frequency electrode during the on period, controlling the first bias power supply to supply the electrical bias to the substrate support portion during the on-period; controlling the second bias power supply so as to apply the negative voltage having a first absolute value to the upper electrode during a first period including the start time of the on period, controlling the second bias power supply to apply the negative voltage having a second absolute value to the upper electrode during a second period following the first period within the on-period; and The first absolute value is smaller than the second absolute value.

[0066] [E2] A plasma processing apparatus as described in E1, wherein The above-mentioned electric bias is a bias high frequency power with a bias frequency, or a voltage pulse periodically generated at a time interval of the inverse of the bias frequency. The first period has a length of at least four times the following period, which has a time length that is the reciprocal of the bias frequency from the starting point.

[0067] [E3] As described in E2, the plasma processing device, wherein the first period has a length less than 8 times or less than 10 times the length of the cycle.

[0068] [E4] A plasma processing device as described in any one of items E1 to E3, wherein The above-mentioned on period and off period appear alternately. The control unit is configured to control the high-frequency power supply and the first bias power supply so as to stop supplying the high-frequency power and the electrical bias during the off period.

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

[0070] [E6] A plasma processing device as described in any one of items E1 to E5, wherein The upper electrode comprises: A top plate connected to the plasma processing space in the chamber; and The cooling plate has a refrigerant flow path and is arranged on the top plate.

[0071] [E7] A plasma processing device as described in E6, wherein the top plate is formed of silicon.

[0072] [E8] A control method comprises the following steps: During the on-state, a high-frequency power source is supplied from a high-frequency power source to a high-frequency electrode, which is a substrate support portion in the chamber or an upper electrode disposed above the substrate support portion, in order to generate plasma from gas in the chamber of the plasma processing apparatus. During the on-state, a first bias power supply supplies an electrical bias to the substrate support portion in order to feed ions in the chamber into the substrate on the substrate support portion. During a first period including the start time of the on period, a negative voltage having a first absolute value is applied to the upper electrode from a second bias power supply; and During a second period following the first period within the on-period, the negative voltage having a second absolute value is applied from the second bias power supply to the upper electrode; and The first absolute value is smaller than the second absolute value.

[0073] [E9] A plasma processing device comprising: chamber; A substrate support portion, which is disposed in the chamber; An upper electrode is disposed above the substrate support portion and is formed with a plurality of gas holes for introducing gas into the chamber; a high-frequency power supply electrically coupled to the high-frequency electrode serving as the substrate support or the upper electrode and configured to generate source high-frequency power for generating plasma from the gas within the chamber; a first bias power supply electrically coupled to the substrate support portion and configured to generate an electrical bias for feeding ions in the chamber to the substrate on the substrate support portion; A second bias power supply configured to apply a negative voltage to the upper electrode; a detector configured to obtain a detection signal representing the intensity of luminescence in a monitoring pore among the plurality of pores or a signal representing the potential or current value of the upper electrode; and Control Department; The control unit is composed of: Controlling the high frequency power supply to supply the source high frequency power to the high frequency electrode during the on period, controlling the first bias power supply to supply the electrical bias to the substrate support portion during the on-period; When it is determined based on the detection signal that there is no possibility of discharge in the upper electrode, the first control is executed. When it is determined based on the detection signal that there is a possibility of discharge in the upper electrode, executing the second control; The second control mentioned above includes: controlling the second bias power supply so as to apply the negative voltage having a first absolute value to the upper electrode during a first period including the start time of the on period, Controlling the second bias power supply to apply the negative voltage having a second absolute value to the upper electrode during a second period following the first period within the on-period; The first control includes: controlling the second bias power supply to apply the negative voltage having the second absolute value to the upper electrode during the entire on-period; and The first absolute value is smaller than the second absolute value.

[0074] [E10] A plasma processing apparatus as described in E9, wherein The above-mentioned electric bias is a bias high frequency power with a bias frequency, or a voltage pulse periodically generated at a time interval of the inverse of the bias frequency. The first period has a length of at least four times the following period, which has a time length that is the reciprocal of the bias frequency from the starting point.

[0075] [E11] As described in E10, the plasma processing device, wherein the first period has a length less than 8 times or less than 10 times the length of the cycle.

[0076] [E12] A plasma processing apparatus as described in any one of items E9 to E11, wherein The above-mentioned on period and off period appear alternately. The control unit is configured to control the high-frequency power supply and the first bias power supply so as to stop supplying the high-frequency power and the electrical bias during the off period.

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

[0078] [E14] A plasma processing apparatus as described in any one of items E9 to E13, wherein The upper electrode comprises: A top plate connected to the plasma processing space in the chamber; and The cooling plate has a refrigerant flow path and is arranged on the top plate.

[0079] [E15] A plasma processing device as described in E14, wherein the top plate is formed of silicon.

[0080] [E16] The plasma processing device as described in any one of items E9 to E15, wherein the control unit is configured to perform the second control when the luminous intensity, the potential, or the current value specified by the detection signal is above or greater than a threshold value.

[0081] [E17] A plasma processing device as described in any one of items E9 to E15, wherein the control unit is configured to execute the second control when the difference between the luminous intensity, the potential, or the current value specified by the detection signal and the normal value of the luminous intensity, the potential, or the current value is above a threshold or greater than a threshold.

[0082] [E18] A control method comprises the following steps: During the on-state, a high-frequency power source is supplied from a high-frequency power source to a high-frequency electrode, which is a substrate support portion in the chamber or an upper electrode disposed above the substrate support portion, in order to generate plasma from gas in the chamber of the plasma processing apparatus. During the on-state, a first bias power supply supplies an electrical bias to the substrate support portion in order to feed ions in the chamber into the substrate on the substrate support portion. executing a first control when it is determined based on a detection signal that there is no possibility of discharge in the upper electrode, the detection signal being a signal indicating the luminous intensity in a plurality of gas holes in the upper electrode for monitoring the gas introduction into the chamber, or a signal indicating the potential or current value of the upper electrode; and When it is determined based on the detection signal that there is a possibility of discharge in the upper electrode, executing the second control; The second control mentioned above includes: During a first period including the start time of the on period, a negative voltage having a first absolute value is applied from a second bias power supply to the upper electrode. During a second period following the first period within the on-period, the negative voltage having a second absolute value is applied from the second bias power supply to the upper electrode; The first control includes: applying the negative voltage having the second absolute value from the second bias power supply to the upper electrode during the entire on period; and The first absolute value is smaller than the second absolute value.

[0083] Based on the above description, it should be understood that the various embodiments of the present invention are described in this specification for illustrative purposes only and that various modifications may be made without departing from the scope and spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit of the present invention are indicated by the appended claims.

[0084] 1,1B: Plasma processing equipment 2: Control Department 2a: Computer 2a1: Processing Department 2a2: Memory 2a3: Communication Interface 10: Chamber 10a: Side wall 10e: Gas exhaust port 10s: Plasma processing space 11:Substrate support department 13:Shower head 13a: Gas supply port 13b: Gas diffusion chamber 13c: Gas inlet 14: Upper electrode 20: Gas supply unit 21: Gas source 22: Flow controller 30: Power supply 31:RF power supply 31a: 1st RF generating unit 31b: Second RF generating unit 32: DC power supply 32a: 1st DC generating unit 32b: Second DC generating unit 40: Exhaust system 50: High frequency power supply 50m,51m:matcher 51: 1st bias power supply 52: Second bias power supply 60: Cooler unit 70: Detector 71s: Optical sensor 72s: Electrical Sensor 111: Ontology Department 111a: Central area 111b: Ring region 112: Ring assembly 141: Top plate 142: Cooling plate 142f: Refrigerant flow path 1110:Abutment 1110a: Flow path 1111:Electrostatic chuck 1111a: Ceramic components 1111b: Electrostatic electrode CY: Waveform period EB: electrical bias HF: Source high frequency power LF: Bias high frequency power MT,MTB:Method P 1: Period 1 P 2: Period 2 P OFF: Off period P ON: On period ST1, ST2, STa~STf, STJ, STJB: Steps UEV: Negative voltage V1, V2, V3: voltage levels VP: Voltage pulse W: substrate

Claims

1. A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; an upper electrode disposed above the substrate support and having a plurality of vent holes for introducing gas into the chamber; a high-frequency power supply electrically coupled to the high-frequency electrode, which is the substrate support or the upper electrode, and configured to generate source high-frequency power in the chamber for generating plasma from gas; a first bias power supply electrically coupled to the substrate support and configured to generate an electrical bias voltage for feeding ions from the chamber onto a substrate on the substrate support; a second bias power supply configured to apply a negative voltage to the upper electrode; and a control unit; wherein the control unit is configured to control the high-frequency power supply to supply the source high-frequency power to the high-frequency electrode during an on-time period, and to control the first bias power supply to supply the electrical bias voltage to the substrate support during the on-time period. The second bias power supply is controlled to apply a negative voltage with a first absolute value to the upper electrode during a first period, including the start point of the aforementioned turn-on period; the second bias power supply is controlled to apply a negative voltage with a second absolute value to the upper electrode during a second period after the first period within the aforementioned turn-on period; and the first absolute value is less than the second absolute value.

2. The plasma processing apparatus of claim 1, wherein the bias voltage is a bias high-frequency power having a bias frequency, or a voltage pulse generated periodically at a time interval equal to the reciprocal of the bias frequency, wherein the first period has a length of more than four times the period, the period having a duration equal to the reciprocal of the bias frequency from the aforementioned start point.

3. The plasma processing apparatus of claim 2, wherein the first period is 8 times or less or 10 times the length of the aforementioned cycle.

4. The plasma processing apparatus of any one of claims 1 to 3, wherein the aforementioned turn-on period alternates with the turn-off period, wherein the aforementioned control unit is configured to control the aforementioned high-frequency power supply and the aforementioned first bias power supply to stop the supply of the aforementioned high-frequency power and the supply of the aforementioned bias voltage during the aforementioned turn-off period.

5. The plasma processing apparatus of claim 4, wherein the control unit is configured to control the second bias power supply to apply a negative voltage having a third absolute value that is greater than the second absolute value to the upper electrode during the disconnection period.

6. The plasma processing apparatus of any one of claims 1 to 3, wherein the upper electrode comprises: a top plate which is connected to the plasma processing space within the chamber; and a cooling plate having a refrigerant flow path and disposed on the top plate.

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

8. A control method for a plasma processing apparatus, comprising the following steps: During a turn-on period, in order to generate plasma from gas in a chamber of the plasma processing apparatus, supplying source high-frequency power from a high-frequency power source to a high-frequency electrode that is a substrate support portion in the chamber or an upper electrode disposed above the substrate support portion; During the turn-on period, in order to feed ions in the chamber to a substrate on the substrate support portion, supplying an electrical bias voltage from a first bias power source to the substrate support portion; During a first period including the start point of the turn-on period, applying a negative voltage having a first absolute value to the upper electrode from a second bias power source; and During a second period after the first period within the turn-on period, applying the negative voltage having a second absolute value to the upper electrode from the second bias power source; wherein the first absolute value is less than the second absolute value.

9. A plasma treatment apparatus comprising: a chamber; A substrate support portion disposed within the aforementioned cavity; an upper electrode disposed above the substrate support portion and having a plurality of vent holes for introducing gas into the aforementioned cavity; a high-frequency power supply electrically coupled to the high-frequency electrode serving as the substrate support portion or the upper electrode, and configured to generate source high-frequency power within the aforementioned cavity for generating plasma from gas; a first bias power supply electrically coupled to the substrate support portion and configured to generate an electrical bias voltage for feeding ions from the aforementioned cavity to the substrate on the substrate support portion; a second bias power supply configured to apply a negative voltage to the upper electrode; a detector configured to acquire a detection signal, which is a signal representing the luminous intensity in the monitoring vent holes among the plurality of vent holes or a signal representing the potential or current value of the upper electrode; and a control unit; the control unit is configured to control the high-frequency power supply to supply source high-frequency power to the high-frequency electrode during the on-time period. The first bias power supply is controlled to supply the electrical bias voltage to the substrate support portion during the above-mentioned turn-on period. When it is determined based on the above-mentioned detection signal that there is no possibility of discharge in the above-mentioned upper electrode, the first control is executed. When it is determined based on the above-mentioned detection signal that there is a possibility of discharge in the above-mentioned upper electrode, the second control is executed. The second control includes: controlling the second bias power supply to apply a negative voltage with a first absolute value to the upper electrode during a first period, including the start point of the aforementioned on-time; and controlling the second bias power supply to apply a negative voltage with a second absolute value to the upper electrode during a second period following the first period within the aforementioned on-time; the first control includes: controlling the second bias power supply to apply a negative voltage with a second absolute value to the upper electrode throughout the entire aforementioned on-time; and the first absolute value is less than the second absolute value.

10. The plasma processing apparatus of claim 9, wherein the bias voltage is a bias high-frequency power having a bias frequency, or a voltage pulse generated periodically at a time interval equal to the reciprocal of the bias frequency, wherein the first period has a length of more than four times the period having a duration equal to the reciprocal of the bias frequency from the aforementioned start point.

11. The plasma processing apparatus of claim 10, wherein the first period is 8 times or less or 10 times the length of the aforementioned period.

12. The plasma processing apparatus of any one of claims 9 to 11, wherein the aforementioned turn-on period alternates with the turn-off period, wherein the aforementioned control unit is configured to control the aforementioned high-frequency power supply and the aforementioned first bias power supply to stop the supply of the aforementioned high-frequency power and the supply of the aforementioned bias voltage during the aforementioned turn-off period.

13. The plasma processing apparatus of claim 12, wherein the control unit is configured to control the second bias power supply to apply a negative voltage having a third absolute value that is greater than the second absolute value to the upper electrode during the disconnection period.

14. The plasma processing apparatus of any one of claims 9 to 11, wherein the upper electrode comprises: a top plate connected to the plasma processing space within the chamber; and a cooling plate having a refrigerant flow path and disposed on the top plate.

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

16. The plasma processing apparatus of any one of claims 9 to 11, wherein the control unit is configured to perform the second control when the light intensity, the potential, or the current value specified based on the detection signal is above or greater than a threshold.

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

18. A control method for a plasma processing apparatus, comprising the following steps: During a power-on period, in order to generate plasma from gas in a chamber of the plasma processing apparatus, supplying extremely high frequency power from a high-frequency power source to a high-frequency electrode of a substrate support portion or an upper electrode disposed above the substrate support portion in the chamber; During the power-on period, in order to feed ions from the chamber to the substrate on the substrate support portion, supplying an electrical bias voltage to the substrate support portion from a first bias power source; When it is determined, based on a detection signal, that there is no possibility of discharge in the upper electrode, executing a first control, the detection signal being a signal representing the luminescence intensity in a plurality of pores of the upper electrode used for monitoring gas introduction into the chamber, or a signal representing the potential or current value of the upper electrode; and When it is determined, based on the detection signal, that there is a possibility of discharge in the upper electrode, executing a second control; The second control comprises the following steps: During a first period, including the start point of the aforementioned on-time, a negative voltage having a first absolute value is applied to the upper electrode from the second bias power supply; and during a second period following the first period within the aforementioned on-time, a negative voltage having a second absolute value is applied to the upper electrode from the second bias power supply; the aforementioned first control includes: During the entire aforementioned turn-on period, a negative voltage having the aforementioned second absolute value is applied from the aforementioned second bias power supply to the aforementioned upper electrode; and the aforementioned first absolute value is less than the aforementioned second absolute value.

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