Plasma processing method and plasma processing apparatus

Abstract

Disclosed is a plasma processing method comprising a step (a) for placing a substrate on a substrate support surface of a substrate support unit provided in the chamber of a plasma processing apparatus. The plasma processing method further comprises a step (b) for etching a film of the substrate by means of plasma. The plasma processing method further comprises a step (c) for cleaning the chamber by means of plasma. In step (b) and step (c), a bias voltage including a pulse of DC voltage and having a pulse waveform is periodically applied to a bias electrode of the substrate support unit. The bias voltage has a bias frequency that is the inverse of the time length of the waveform period of the pulse waveform. The bias frequency in step (c) is higher than the bias frequency in step (b).

Description

Technical Field

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

Background Art

[0002] A plasma processing apparatus is used for etching a film on a substrate. When etching a film on a substrate in a plasma processing apparatus, by-products are formed on the surface inside the chamber. In order to remove this by-product, cleaning of the chamber is performed. The cleaning of the chamber is described in Patent Document 1 below.

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 enhancing the removal performance by cleaning substances adhering to the surface inside the chamber.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing method is provided. The plasma processing method includes a step (a) of placing a substrate on a substrate support surface of a substrate support provided in a chamber of a plasma processing apparatus. The plasma processing method further includes a step (b) of etching a film of the substrate using plasma generated from an etching gas in the chamber. The plasma processing method further includes a step (c) of cleaning the chamber using plasma generated from a cleaning gas in the chamber. In steps (b) and (c), a bias voltage including a pulse of a DC voltage and having a pulse waveform is periodically applied to a bias electrode of the substrate support. The bias voltage has a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform. The bias frequency in step (c) is higher than the bias frequency in step (b).

Advantages of the Invention

[0006] According to one exemplary embodiment, the removal performance by cleaning of substances adhering to the surface in the chamber is enhanced.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out 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] FIG. 1 is a flowchart of a plasma processing method according to one exemplary embodiment. The plasma processing method shown in FIG. 1 (hereinafter referred to as "method MT") is performed using a plasma processing apparatus.

[0010] FIG. 2 is a diagram for explaining a configuration example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Further, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas discharge port is connected to an exhaust system 40 described later. The substrate support unit 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0011] The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), ECR plasma (Electron-Cyclotron-resonance plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like.

[0012] 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 may 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 may be configured to read a program from the storage unit 2a2 and perform various control operations by executing the read program. This program includes computer-executable instructions for causing the plasma processing apparatus 1 to execute various processes according to the exemplary embodiments described later. This program may be stored in advance in the storage unit 2a2, 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).

[0013] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. FIG. 3 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0014] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. 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 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0015] 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 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.

[0016] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member.

[0017] 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.

[0018] Further, the substrate support 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are disposed within the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support 11 may include a heat transfer gas supply unit configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0019] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. In addition to the shower head 13, the gas introduction part may include one or a plurality of side gas injectors (SGI) attached to one or a plurality of openings formed in the side wall 10a.

[0020] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure control type flow controller. Further, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsing the flow rate of at least one process gas.

[0021] The exhaust system 40 can be connected to, for example, a gas discharge port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0022] The power supply system 30 includes a high-frequency power supply 31 and a bias power supply 32. The high-frequency power supply 31 constitutes the plasma generation unit 12 in one embodiment. The high-frequency power supply 31 is configured to generate source high-frequency power RF. The source high-frequency power RF has a source frequency f RF That is, the source high-frequency power RF has a frequency of the source frequency fRF It has a sinusoidal waveform. The source frequency f RF can be a frequency within the range of 10 MHz to 150 MHz. The high-frequency power supply 31 is electrically connected to the high-frequency electrode via a matcher 33 and is configured to supply source high-frequency power RF to the high-frequency electrode. The high-frequency electrode may be a conductive member of the base 1110, at least one electrode provided in the ceramic member 1111a, or an upper electrode. The matcher 33 has a variable impedance. The variable impedance of the matcher 33 is set to reduce reflection from the load of the source high-frequency power RF. When the source high-frequency power RF is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber 10.

[0023] The bias power supply 32 is configured to generate a bias voltage BE. The bias power supply 32 is electrically coupled to the substrate support 11. The bias power supply 32 is electrically connected to a bias electrode in the substrate support 11 and is configured to periodically apply the bias voltage BE to the bias electrode. The bias electrode may be a conductive member of the base 1110 or at least one electrode provided in the ceramic member 1111a. When the bias voltage BE is applied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0024] Hereinafter, refer to FIG. 4 together with FIG. 3. FIG. 4 is an example of a timing chart related to a plasma processing apparatus according to one exemplary embodiment. As shown in FIG. 4, the bias voltage BE has a pulse waveform and is periodically applied to the bias electrode. The pulse waveform includes voltage pulses. The voltage pulses in the pulse waveform may be DC voltage pulses. The voltage pulses in the pulse waveform may have a negative polarity as shown in FIG. 4. The pulse waveform of the bias voltage BE may be a rectangular wave, a triangular wave, or any waveform. The pulse waveform of the bias voltage BE has a waveform period (refer to waveform period CYb or waveform period CYc in FIG. 4). The bias voltage BE has a bias frequency that is the reciprocal of the time length of the waveform period. The bias frequency is lower than the source frequency. The bias frequency can be set within the range of 100 kHz to 60 MHz.

[0025] Hereinafter, the method MT will be described. Also, the plasma processing apparatus 1 will be described in more detail.

[0026] As shown in FIG. 1, the method MT includes step STa, step STb, and step STc. The method MT may further include step STd that is performed after step STb and before step STc. The method MT may further include step Ste that is performed after step STb and before step STd.

[0027] In step STa of the method MT, the substrate W is placed on the substrate support surface of the substrate support portion 11. The substrate support surface is the upper surface of the central region 111a or the electrostatic chuck 1111.

[0028] In step STb, the film on the substrate W is etched. In step STb, plasma is generated from the etching gas in the chamber 10. The film may be a silicon-containing film such as a silicon oxide film. The etching gas may contain a fluorocarbon gas. The etching gas may further contain an oxygen-containing gas and / or a fluorine-containing gas. The oxygen-containing gas may be oxygen gas (O2 gas). The fluorine-containing gas may be nitrogen trifluoride gas. In step STb, the film on the substrate W is etched by chemical species such as ions and / or radicals from the plasma.

[0029] In step STb, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, the high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STb, the etching gas is supplied from the gas supply unit 20 into the chamber 10. In step STb, the pressure in the chamber 10 is set to a specified pressure by the exhaust system 40. In step STb, plasma is generated from the etching gas by the plasma generation unit 12. Specifically, source high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrode, and plasma is generated from the etching gas in the chamber 10.

[0030] In step STb, the bias voltage BE is periodically applied from the bias power supply 32 to the bias electrode. The bias frequency of the bias voltage BE in step STb is set to the bias frequency fBb. The bias frequency fBb is the reciprocal of the time length CLb (see FIG. 4) of the waveform period CYb of the pulse waveform of the bias voltage BE in step STb. Also, in step STb, the duty ratio of the pulse waveform of the bias voltage BE is set to the duty ratio ODb. The duty ratio ODb is the value of the ratio or proportion of the time length of the period PONb to the time length of the time length CLb of the waveform period CYb. The period PONb is the period during which the voltage pulse in the bias voltage BE is output within the waveform period CYb.

[0031] In method MT, in step STep after step STb, substrate W is unloaded from chamber 10. Next, in method MT, step STe may be performed. In step STe, the inside of chamber 10 is cleaned with no object placed on the substrate support surface. In step STe, for cleaning, plasma is generated from a cleaning gas inside chamber 10. The cleaning gas used in step STe may contain a fluorocarbon gas. The cleaning gas used in step STe may further contain an oxygen-containing gas. The oxygen-containing gas may be oxygen gas (O2 gas). In step STe, the surface inside chamber 10 is cleaned by chemical species such as ions and / or radicals from the plasma.

[0032] In step STe, gas supply unit 20, exhaust system 40, plasma generation unit 12 (in one example, high-frequency power supply 31), and bias power supply 32 are controlled by control unit 2. In step STe, the cleaning gas is supplied from gas supply unit 20 into chamber 10. In step STe, the pressure inside chamber 10 is set to a specified pressure by exhaust system 40. In step STe, plasma is generated from the cleaning gas by plasma generation unit 12. Specifically, source high-frequency power RF is supplied from high-frequency power supply 31 to the high-frequency electrode, and plasma is generated from the cleaning gas inside chamber 10. In step STe, bias power supply 32 may not apply bias voltage BE to the bias electrode.

[0033] Next, in method MT, step STdp is performed. In step STdp, a dummy substrate is placed on the substrate support surface. Next, in method MT, step STd may be performed. In step STd, the chamber 10 is cleaned with a dummy substrate placed on the substrate support surface. In step STd, plasma is generated from an oxygen-containing gas in the chamber 10 for cleaning. The oxygen-containing gas may be oxygen gas (O2 gas). The gas supplied into the chamber 10 in step STd may be only the oxygen-containing gas. In step STd, the surface inside the chamber 10 is cleaned by chemical species such as ions and / or radicals from the plasma.

[0034] In step STd, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, the high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STd, the oxygen-containing gas is supplied from the gas supply unit 20 into the chamber 10. In step STd, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In step STd, plasma is generated from the oxygen-containing gas by the plasma generation unit 12. Specifically, source high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrode, and plasma is generated from the oxygen-containing gas in the chamber 10. In step STd, the bias power supply 32 may not apply a bias voltage BE to the bias electrode.

[0035] Next, in method MT, process STc is performed. In process STc, the chamber 10 is cleaned. Process STc may be performed with a dummy substrate placed on the substrate support surface. In process STc, plasma is generated from the cleaning gas inside the chamber 10. The cleaning gas may contain a fluorocarbon gas such as CF4 gas. The cleaning gas may further contain an oxygen-containing gas. The oxygen-containing gas may be oxygen gas (O2 gas). The cleaning gas may further contain a noble gas. The noble gas may be argon gas. In process STc, the surface inside the chamber 10 is cleaned by chemical species such as ions and / or radicals from the plasma.

[0036] In process STc, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, the high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In process STc, the cleaning gas is supplied from the gas supply unit 20 into the chamber 10. In process STc, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In process STc, plasma is generated from the cleaning gas by the plasma generation unit 12. Specifically, source high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrode, and plasma is generated from the cleaning gas inside the chamber 10.

[0037] In process STc, a bias voltage BE is periodically applied from the bias power supply 32 to the bias electrode. The bias frequency of the bias voltage BE in process STc is set to the bias frequency fBc. The bias frequency fBc is the reciprocal of the time length CLc (see FIG. 4) of the waveform period CYc of the pulse waveform of the bias voltage BE in process STc. Also, in process STc, the duty ratio of the pulse waveform of the bias voltage BE is set to the duty ratio ODc. The duty ratio ODc is the value of the ratio or proportion of the time length of the period PONc to the time length of the waveform period CYc. The period PONc is the period during which the voltage pulse in the bias voltage BE is output within the waveform period CYc.

[0038] In step STc, the bias power supply 32 sets the bias frequency fBc to a value higher than the bias frequency fBb in step STb. Thereby, the removal performance by cleaning in step STc of substances such as metal adhering to the surface in the chamber 10 is enhanced. Note that the metal may include aluminum and / or yttrium. These metals are generated from the surface in the chamber 10 exposed to plasma in the etching of step STb and adhere to the surface in the chamber 10.

[0039] In step STc, the bias power supply 32 may set the duty ratio ODc to a value higher than the duty ratio ODb in step STb. In this case, the energy of the ions supplied to substances such as metal adhering to the surface in the chamber 10 in step STc becomes higher. Therefore, the removal performance of the substance in step STc is further enhanced.

[0040] In addition to, or instead of, setting the bias frequency fBc to a value higher than the bias frequency fBb in step STc, the bias power supply 32 may set the absolute value of the voltage level of the voltage pulse in the bias voltage BE in step STc to a value larger than the absolute value of the voltage level of the voltage pulse in the bias voltage BE in step STb.

[0041] Although various exemplary embodiments have been described above, without being limited to the above-described exemplary embodiments, various additions, omissions, substitutions, and changes may be made. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0042] For example, in another embodiment, the plasma processing apparatus may include one or more bias power supplies as described in U.S. Patent Application Publication No. 2021 / 0074524 (U.S. Application No. 17 / 015100). The plasma processing apparatus may supply a bias voltage BE as bias power to two or more bias electrodes within the substrate support portion from one or more bias power supplies as described in the same U.S. Patent Application Publication. Such a plasma processing apparatus can be used in the plasma processing method described above. Note that the entire content of the same U.S. application is incorporated herein by reference.

[0043] Hereinafter, the first and second experiments performed using the plasma processing apparatus 1 for the evaluation of the method MT will be described. In each of the first and second experiments, the method MT was executed with a chip attached on the ring assembly 112. In step STb, the silicon oxide film of the sample substrate was etched using an etching gas containing a fluorocarbon gas, an oxygen gas, and a nitrogen trifluoride gas. Next, in step STe, the chamber 10 was cleaned using a cleaning gas containing a fluorocarbon gas and an oxygen gas with no object placed on the substrate support surface. Next, in step STd, the chamber 10 was cleaned using an oxygen gas with a dummy substrate placed on the substrate support surface. Then, in step STc, the chamber 10 was cleaned using a cleaning gas containing a fluorocarbon gas, an argon gas, and an oxygen gas with a dummy substrate placed on the substrate support surface. The bias frequency fBb in step STb was 400 kHz. In the first experiment, the bias frequency fBc in step STc was set to 400 kHz. In the second experiment, the bias frequency fBc in step STc was set to 600 kHz.

[0044] In the first and second experiments, 1 cm on the chip after step STc 2The deposition amounts of aluminum (Al) and yttrium (Y) in the vicinity were measured. The results are shown in FIG. 5. In FIG. 5, the horizontal axis indicates the bias frequency in process STc, and the vertical axis represents the metal deposition amount per 1 cm on the chip after process STc. 2 As shown in FIG. 5, the deposition amounts of aluminum and yttrium when the bias frequency in process STc was 600 kHz were lower than the corresponding deposition amounts when the bias frequency in process STc was 400 kHz. From this, it was confirmed that by setting the bias frequency in process STc to a frequency higher than the bias frequency in process STb, the removal performance by cleaning in process STc of substances such as metals adhering to the surface in chamber 10 was enhanced.

[0045] Here, various exemplary embodiments included in the present disclosure are described in the following [E1] to [E25].

[0046] [E1] (a) A step of placing a substrate on a substrate support surface of a substrate support portion provided in a chamber of a plasma processing apparatus; (b) A step of etching a film of the substrate using plasma generated from an etching gas in the chamber; (c) A step of cleaning the chamber using plasma generated from a cleaning gas in the chamber; including in the above (b) and (c), a bias voltage including a pulse of a direct current voltage and having a pulse waveform is periodically applied to a bias electrode of the substrate support portion, the bias voltage has a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform, the bias frequency in the above (c) is higher than the bias frequency in the above (b), Plasma processing method.

[0047] [E2] The plasma processing method according to claim 1, wherein the duty ratio of the pulse waveform of the bias voltage in (c) is higher than the duty ratio in (b).

[0048] [E3] The plasma processing method according to E1 or E2, wherein each of the etching gas and the cleaning gas contains a fluorocarbon gas.

[0049] [E4] The plasma processing method according to E3, wherein the cleaning gas further contains an oxygen-containing gas.

[0050] [E5] (d) Further including a step of cleaning the chamber using plasma generated from an oxygen-containing gas in the chamber with a dummy substrate placed on the substrate support between (b) and (c), In (d), the bias voltage is not applied to the bias electrode. The plasma processing method according to any one of E1 to E4.

[0051] [E6] (e) Further including a step of cleaning the chamber using plasma formed from another cleaning gas in the chamber with no object placed on the substrate support surface between (b) and (d), the plasma processing method according to E5.

[0052] [E7] In (e), the bias voltage is not applied to the bias electrode, the plasma processing method according to E6.

[0053] [E8] The plasma processing method according to E6 or E7, wherein the another cleaning gas contains a fluorocarbon gas.

[0054] [E9] The other cleaning gas further contains an oxygen-containing gas, and is the plasma processing method described in E8.

[0055] [E10] The step (c) is performed with a dummy substrate placed on the substrate support surface, and is the plasma processing method according to any one of E1 to E9.

[0056] [E11] The pulse of the DC voltage has a negative polarity, and is the plasma processing method according to any one of E1 to E10.

[0057] [E12] The absolute value of the voltage level of the voltage pulse in the step (c) is greater than the absolute value of the voltage level of the voltage pulse in the step (b), and is the plasma processing method according to any one of E1 to E11.

[0058] [E13] A chamber, A substrate support portion provided in the chamber, having a substrate support surface and a bias electrode, A gas supply portion configured to supply gas into the chamber, A plasma generation portion configured to generate plasma in the chamber, A bias power supply configured to periodically apply a bias voltage having a pulse of a DC voltage and having a pulse waveform to the bias electrode, the bias voltage having a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform, A control portion configured to control the gas supply portion, the plasma generation portion, and the bias power supply, Comprising, The control portion, (b) Control the gas supply portion, the plasma generation portion, and the bias power supply so as to generate plasma from an etching gas in the chamber and etch the film of the substrate placed on the substrate support portion. (c) Control the gas supply unit, the plasma generation unit, and the bias power supply so as to generate plasma from the cleaning gas in the chamber to clean the chamber. It is configured as follows. The bias power supply In the above (b) and (c), apply the bias voltage to the bias electrode periodically. In the above (c), set the bias frequency to a frequency higher than the bias frequency in the above (b). It is configured as follows. Plasma processing apparatus.

[0059] [E14] The bias power supply is configured to set the duty ratio of the pulse waveform of the bias voltage in the above (c) to a value higher than the duty ratio in the above (b) in the plasma processing apparatus according to E13.

[0060] [E15] Each of the etching gas and the cleaning gas contains a fluorocarbon gas in the plasma processing apparatus according to E13 or E14.

[0061] [E16] The cleaning gas further contains an oxygen-containing gas in the plasma processing apparatus according to E15.

[0062] [E17] The control unit (d) Between the above (b) and (c), control the gas supply unit and the bias power supply so as to generate plasma from the oxygen-containing gas in the chamber to clean the chamber with a dummy substrate placed on the substrate support portion. It is configured as follows. In the above (d), the bias power supply does not apply the bias voltage to the bias electrode. Plasma processing apparatus according to any one of E13 to E16.

[0063] [E18] The control unit (e) between the said (b) and the said (d), with no object placed on the substrate support surface, generate plasma from another cleaning gas in the chamber to clean the chamber, and control the gas supply unit and the bias power supply is configured as described in E17, the plasma processing apparatus according to E17

[0064] [E19] The bias power supply does not apply the bias voltage to the bias electrode in the said (e), the plasma processing apparatus according to E18

[0065] [E20] The said another cleaning gas contains a fluorocarbon gas, the plasma processing apparatus according to E18 or E19

[0066] [E21] The said another cleaning gas further contains an oxygen-containing gas, the plasma processing apparatus according to E20

[0067] [E22] The said (c) is performed with a dummy substrate placed on the substrate support surface, the plasma processing apparatus according to any one of E13 to E21

[0068] [E23] The pulse of the DC voltage has a negative polarity, the plasma processing apparatus according to any one of E13 to E22

[0069] [E24] The bias power supply is configured to set the absolute value of the voltage level of the voltage pulse in the said (c) to a value larger than the absolute value of the voltage level of the voltage pulse in the said (b), the plasma processing apparatus according to any one of E13 to E23

[0070] [E25] a chamber, It has a substrate support surface and a bias electrode, and a substrate support portion provided in the chamber, a gas supply portion configured to supply gas into the chamber, a plasma generation portion configured to generate plasma in the chamber, a bias power supply configured to periodically apply a bias voltage having a pulse waveform including a direct current voltage pulse to the bias electrode, wherein the bias voltage has a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform, and the bias power supply, a control portion configured to control the gas supply portion, the plasma generation portion, and the bias power supply, and is provided with, the control portion, (b) controls the gas supply portion, the plasma generation portion, and the bias power supply so as to generate plasma from an etching gas in the chamber and etch a film of a substrate placed on the substrate support portion, (c) controls the gas supply portion, the plasma generation portion, and the bias power supply so as to generate plasma from a cleaning gas in the chamber and clean the chamber, is configured as such, the bias power supply, in the above (b) and (c), periodically applies the bias voltage to the bias electrode, sets the absolute value of the voltage level of the voltage pulse in the above (c) to a value larger than the absolute value of the voltage level of the voltage pulse in the above (b), is configured as such, a plasma processing apparatus.

[0071] From the above description, it will be understood that the various embodiments of the present disclosure are described herein for the purpose of illustration, and various changes can be made without departing from the scope and gist of the present disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and gist are indicated by the appended claims.

Description of Symbols

[0072] 1... Plasma processing apparatus, 10... Chamber, 11... Substrate support unit, 12... Plasma generation unit, 20... Gas supply unit, 31... High-frequency power supply, 32... Bias power supply.

Claims

1. (a) A step of placing a substrate on a substrate support surface of a substrate support provided in a chamber of a plasma processing apparatus; (b) A step of etching a film of the substrate using plasma generated from an etching gas in the chamber; (c) A step of cleaning the chamber using plasma generated from a cleaning gas in the chamber; comprising: In the above (b) and (c), a bias voltage including a pulse of a DC voltage and having a pulse waveform is periodically applied to a bias electrode of the substrate support; The bias voltage has a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform; The bias frequency in the above (c) is higher than the bias frequency in the above (b); A plasma processing method.

2. The plasma processing method according to claim 1, wherein a duty ratio of the pulse waveform of the bias voltage in the above (c) is higher than the duty ratio in the above (b).

3. The plasma processing method according to claim 1, wherein each of the etching gas and the cleaning gas contains a fluorocarbon gas.

4. The plasma processing method according to claim 3, wherein the cleaning gas further contains an oxygen-containing gas.

5. (d) Further comprising a step of cleaning the chamber using plasma generated from an oxygen-containing gas in the chamber with a dummy substrate placed on the substrate support between the above (b) and the above (c); In the above (d), the bias voltage is not applied to the bias electrode; The plasma processing method according to any one of claims 1 to 4.

6. (e) Further comprising a step of cleaning the chamber using plasma formed from another cleaning gas in the chamber with no object placed on the substrate support surface between the above (b) and the above (d), the plasma processing method according to claim 5.

7. The plasma processing method according to claim 6, wherein the bias voltage is not applied to the bias electrode in the above (e).

8. The plasma processing method according to claim 6, wherein the another cleaning gas contains a fluorocarbon gas.

9. The plasma processing method according to claim 8, wherein the another cleaning gas further contains an oxygen-containing gas.

10. The above (c) is the plasma processing method according to any one of claims 1 to 4, which is performed with a dummy substrate placed on the substrate support surface.

11. The pulse of the DC voltage has a negative polarity, and it is the plasma processing method according to any one of claims 1 to 4.

12. The absolute value of the voltage level of the voltage pulse in the above (c) is larger than the absolute value of the voltage level of the voltage pulse in the above (b), and it is the plasma processing method according to any one of claims 1 to 4.

13. A chamber, A substrate support portion provided in the chamber, having a substrate support surface and a bias electrode, A gas supply portion configured to supply gas into the chamber, A plasma generation portion configured to generate plasma in the chamber, A bias power supply configured to periodically apply a bias voltage having a pulse waveform including a pulse of a DC voltage to the bias electrode, and the bias voltage has a bias frequency which is the reciprocal of the time length of the waveform period of the pulse waveform, and this bias power supply, A control portion configured to control the gas supply portion, the plasma generation portion, and the bias power supply, Comprising, The control portion, (b) Control the gas supply portion, the plasma generation portion, and the bias power supply so as to generate plasma from an etching gas in the chamber and etch the film of the substrate placed on the substrate support portion. (c) Control the gas supply portion, the plasma generation portion, and the bias power supply so as to generate plasma from a cleaning gas in the chamber and clean the chamber. It is configured as such, The bias power supply, In the above (b) and the above (c), periodically apply the bias voltage to the bias electrode, Set the bias frequency in the above (c) to a frequency higher than the bias frequency in the above (b). It is configured as such. A plasma processing apparatus.

14. The bias power supply is configured to set the duty ratio of the pulse waveform of the bias voltage in the above (c) to a value higher than the duty ratio in the above (b), and it is the plasma processing apparatus according to claim 13.

15. Each of the etching gas and the cleaning gas contains a fluorocarbon gas, and it is the plasma processing apparatus according to claim 13.

16. The plasma processing apparatus according to claim 15, wherein the cleaning gas further contains an oxygen-containing gas.

17. The control unit (d) Between the above (b) and the above (c), with a dummy substrate placed on the substrate support portion, the gas supply unit and the bias power supply are controlled to generate plasma from the oxygen-containing gas in the chamber to clean the chamber. is configured as In the above (d), the bias power supply does not apply the bias voltage to the bias electrode. The plasma processing apparatus according to any one of claims 13 to 16.

18. The control unit (e) Between the above (b) and the above (d), with no object placed on the substrate support surface, the gas supply unit and the bias power supply are controlled to generate plasma from another cleaning gas in the chamber to clean the chamber. The plasma processing apparatus according to claim 17, which is configured as

19. In the above (e), the bias power supply does not apply the bias voltage to the bias electrode. The plasma processing apparatus according to claim 18.

20. The plasma processing apparatus according to claim 18, wherein the another cleaning gas contains a fluorocarbon gas.

21. The plasma processing apparatus according to claim 20, wherein the another cleaning gas further contains an oxygen-containing gas.

22. In the above (c), it is performed with a dummy substrate placed on the substrate support surface. The plasma processing apparatus according to any one of claims 13 to 16.

23. The plasma processing apparatus according to any one of claims 13 to 16, wherein the pulse of the DC voltage has a negative polarity.

24. The bias power supply is configured to set the absolute value of the voltage level of the voltage pulse in the above (c) to a value larger than the absolute value of the voltage level of the voltage pulse in the above (b). The plasma processing apparatus according to any one of claims 13 to 16.

25. A chamber, A substrate support portion provided in the chamber, having a substrate support surface and a bias electrode, A gas supply unit configured to supply gas into the chamber, A plasma generation unit configured to generate plasma in the chamber, A bias power supply configured to periodically apply a bias voltage having a pulse waveform including a direct current voltage pulse to the bias electrode, the bias voltage having a bias frequency that is the reciprocal of the time length of the waveform period of the pulse waveform, the bias power supply, A control unit configured to control the gas supply unit, the plasma generation unit, and the bias power supply, Comprising, The control unit is, (b) Control the gas supply unit, the plasma generation unit, and the bias power supply so as to generate plasma from an etching gas in the chamber and etch the film of the substrate placed on the substrate support unit, (c) Control the gas supply unit, the plasma generation unit, and the bias power supply so as to generate plasma from a cleaning gas in the chamber and clean the chamber, Is configured as, The bias power supply is, In the above (b) and (c), the bias voltage is periodically applied to the bias electrode, In the above (c), the absolute value of the voltage level of the voltage pulse is set to a value larger than the absolute value of the voltage level of the voltage pulse in the above (b), Is configured as, Plasma processing apparatus.

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