Plasma treatment method and plasma treatment apparatus

Abstract

Provided is a plasma processing method that is performed in a plasma processing apparatus. The plasma processing method comprises a step (a) for applying a voltage to a lower electrode of a substrate support unit, in a state in which a chamber of the plasma processing apparatus is supplied with a gas. The substrate support unit is provided in the chamber. The plasma processing method further comprises a step (b) for generating plasma by supplying a high frequency after application of the voltage to the lower electrode is started in step (a). The step (a) and the step (b) are performed in a state in which no object is placed on a substrate support surface of the substrate support unit.

Description

Technical Field

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

Background Art

[0002] Plasma processing apparatuses are used in the processing of substrates. When a substrate is processed in a plasma processing apparatus, the wall surface inside the chamber is contaminated with by-products. Therefore, cleaning of the chamber is performed. Patent Document 1 discloses a method for cleaning a chamber. This cleaning method uses microwaves to generate plasma during cleaning.

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 shortening the time required for plasma ignition and reducing its variation in plasma processing performed in a state where no object is placed on the substrate support surface of a substrate support.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma treatment method performed in a plasma processing apparatus is provided. The plasma treatment method includes step (a) applying a voltage to the lower electrode of a substrate support while gas is supplied into the chamber of the plasma processing apparatus. The substrate support is provided in the chamber. The plasma treatment method further includes step (b) generating plasma by supplying high frequency after the application of voltage to the lower electrode has started in step (a). Steps (a) and (b) are performed while no object is placed on the substrate support surface of the substrate support. [Effects of the Invention]

[0006] According to this disclosure, in plasma processing performed when no object is placed on the substrate support surface of the substrate support portion, it is possible to shorten the time required for plasma ignition and reduce variations in that time. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view showing a plasma processing apparatus according to one exemplary embodiment. [Figure 2] A plan view showing an example of a slot plate. [Figure 3] This is a plan view showing an example of a dielectric window. [Figure 4] This is a cross-sectional view taken along the line IV-IV in Figure 3. [Figure 5] This is a plan view showing the state in which the slot plate shown in Figure 2 is placed on the dielectric window shown in Figure 3. [Figure 6] This is a flowchart showing a plasma processing method according to one exemplary embodiment. [Figure 7] This is a flowchart detailing step S3 of a plasma treatment method according to one exemplary embodiment. [Modes for carrying out the invention]

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

[0009] Figure 1 is a schematic cross-sectional view showing a plasma processing apparatus according to one exemplary embodiment. The plasma processing apparatus 10 shown in Figure 1 includes a chamber 12. The chamber 12 provides a processing space S for housing a substrate W.

[0010] The chamber 12 includes a side wall 12a. The chamber 12 may further include a bottom portion 12b and a top portion 12c. The side wall 12a has a substantially cylindrical shape that extends in the direction in which the axis Z extends. This axis Z is, for example, the axis that passes vertically through the center of the mounting base, which will be described later. In one embodiment, the central axis of the side wall 12a coincides with the axis Z. The inner diameter of this side wall 12a is, for example, 540 mm.

[0011] The bottom portion 12b is provided on the lower end side of the side wall 12a. The upper end of the side wall 12a is open. The upper end opening of the side wall 12a is closed by a dielectric window 18. The dielectric window 18 is sandwiched between the upper end of the side wall 12a and the top portion 12c. A sealing member SL1 may be interposed between the dielectric window 18 and the upper end of the side wall 12a. The sealing member SL1 is, for example, an O-ring and contributes to the sealing of the chamber 12.

[0012] The plasma processing apparatus 10 further comprises a substrate support section 20 provided within the chamber 12. The substrate support section 20 is located below the dielectric window 18. For example, the distance between the lower surface of the dielectric window 18 and the upper surface of the substrate support section 20 is 245 mm. In one embodiment, the substrate support section 20 includes a base LE and an electrostatic chuck ESC.

[0013] The base LE includes a first plate 22a and a second plate 22b. Both the first plate 22a and the second plate 22b have a substantially disc shape and are made of, for example, aluminum. The first plate 22a is supported by a cylindrical support SP1. The support SP1 extends vertically upward from the bottom 12b. The second plate 22b is provided on the first plate 22a and is electrically connected to the first plate 22a.

[0014] The base LE is electrically connected to a high-frequency power supply (RFG) (an example of a power supply) via a feed rod PFR and a matching unit MU. The high-frequency power supply RFG supplies high-frequency bias power to the base LE. The high-frequency bias power generated by the high-frequency power supply RFG may have a constant frequency, for example, 13.65 MHz, suitable for controlling the energy of ions drawn into the substrate W. The matching unit MU houses a matching circuit for matching the impedance on the high-frequency power supply RFG side with the impedance on the load side, mainly electrodes, plasma, and chamber 12. This matching circuit may include, for example, a blocking capacitor for self-bias generation.

[0015] The electrostatic chuck ESC is provided on the second plate 22b. The electrostatic chuck ESC provides a substrate support surface MR for placing the substrate W on the processing space S side. The substrate support surface MR is a substantially circular region substantially perpendicular to the axis Z, and may have a diameter substantially the same as the diameter of the substrate W or slightly smaller than the diameter of the substrate W. Furthermore, this substrate support surface MR constitutes the upper surface of the substrate support portion 20, and the center of the substrate support surface MR, i.e., the center of the substrate support portion 20, is located on the axis Z.

[0016] The electrostatic chuck ESC holds the substrate W by electrostatic attraction force. The electrostatic chuck ESC includes a chuck electrode CE. The chuck electrode is provided within a dielectric. A DC power supply DCS is connected to the chuck electrode CE via a switch SW and a coated wire CL. The electrostatic chuck ESC can attract and hold the substrate W on its upper surface by the Coulomb force generated by the DC voltage applied from the DC power supply DCS. A focus ring FR is provided on the radially outer side of the electrostatic chuck ESC, surrounding the substrate W in an annular shape. The substrate W is transported into the processing space S by a transport device and placed on the electrostatic chuck ESC. The substrate W is then lifted from the electrostatic chuck ESC and transported out of the processing space S by the transport device.

[0017] An annular channel 24g is formed inside the second plate 22b. Coolant is supplied to this channel 24g from the chiller unit via piping PP1. The coolant supplied to channel 24g is recovered by the chiller unit via piping PP3. Furthermore, in the plasma processing apparatus 10, a heat transfer gas, such as He gas, is supplied from the heat transfer gas supply unit via supply pipe PP2 between the upper surface of the electrostatic chuck ESC and the back surface of the substrate W.

[0018] Outside the outer periphery of the substrate support portion 20, that is, a space is provided between the substrate support portion 20 and the side wall 12a. This space forms an exhaust passage VL having an annular shape in plan view. An annular baffle plate 26 having a plurality of through holes formed therein is provided in the middle in the axial direction Z of the exhaust passage VL. The exhaust passage VL is connected to an exhaust pipe 28 that provides an exhaust port 28h. The exhaust pipe 28 is attached to the bottom 12b of the chamber 12. An exhaust device 30 is connected to this exhaust pipe 28. The exhaust device 30 has a pressure regulator and a vacuum pump such as a turbo molecular pump. By this exhaust device 30, the processing space S in the chamber 12 can be decompressed to a desired degree of vacuum. Further, the gas supplied to the substrate W flows along the surface of the substrate W toward the outside of the edge of the substrate W by operating the exhaust device 30, and is exhausted from the outer periphery of the substrate support portion 20 through the exhaust passage VL.

[0019] The plasma processing apparatus 10 may further include heaters HT, HS, HC, and HE as a temperature control mechanism. The heater HT is provided in the top portion 12c and extends annularly so as to surround the antenna 14. Further, the heater HS is provided in the side wall 12a and extends annularly. The heater HC is provided in the second plate 22b or in the electrostatic chuck ESC. The heater HC is provided below the central portion of the substrate support surface MR described above, that is, in a region intersecting the axis Z. Further, the heater HE extends annularly so as to surround the heater HC. The heater HE is provided below the outer edge portion of the substrate support surface MR described above.

[0020] The plasma processing apparatus 10 may further include an antenna 14, a coaxial waveguide 16, a microwave generator 32, a tuner 34, a waveguide 36, and a mode converter 38. These antenna 14, coaxial waveguide 16, dielectric window 18, microwave generator 32, tuner 34, waveguide 36, and mode converter 38 constitute a plasma generation source for exciting the gas introduced into the chamber.

[0021] The microwave generator 32 is a high-frequency source according to one embodiment. The microwave generator 32 generates microwaves with a frequency of, for example, 2.45 GHz. The microwave generator 32 is connected to the top of the coaxial waveguide 16 via a tuner 34, a waveguide 36, and a mode converter 38. The coaxial waveguide 16 extends along its central axis, axis Z.

[0022] The coaxial waveguide 16 includes an outer conductor 16a and an inner conductor 16b. The outer conductor 16a has a cylindrical shape extending along the axis Z. The lower end of the outer conductor 16a is electrically connected to the upper part of a cooling jacket 40 having a conductive surface. The inner conductor 16b is provided inside the outer conductor 16a and coaxially with the outer conductor 16a. The inner conductor 16b has a cylindrical shape extending along the axis Z. The lower end of the inner conductor 16b is connected to the slot plate 44 of the antenna 14.

[0023] Antenna 14 is configured to allow microwaves to be introduced into the chamber 12. In one embodiment, antenna 14 is a radial line slot antenna. This antenna 14 is positioned in an opening formed in the top portion 12c so as to face the substrate support portion 20. Antenna 14 includes a dielectric plate 42, a slot plate 44, and a dielectric window 18. The dielectric plate 42 shortens the wavelength of microwaves and has a substantially disc shape. The dielectric plate 42 is made of, for example, quartz or alumina. This dielectric plate 42 is sandwiched between the slot plate 44 and the lower surface of the cooling jacket 40.

[0024] Figure 2 is a plan view showing an example of a slot plate. The slot plate 44 is thin and disc-shaped. Both sides of the slot plate 44 in the thickness direction are flat. The center CS of the slot plate 44 is located on the axis Z. The slot plate 44 is provided with multiple slot pairs 44p. Each of the multiple slot pairs 44p contains two slot holes 44a and 44b that penetrate in the thickness direction. The planar shape of each slot hole 44a and 44b is an elongated hole shape. In each slot pair 44p, the direction in which the major axis of slot hole 44a extends and the direction in which the major axis of slot hole 44b extends intersect or are perpendicular to each other. These multiple slot pairs 44p are arranged in the circumferential direction. In the example shown in Figure 2, the multiple slot pairs 44p are arranged in the circumferential direction along two concentric circles. On each concentric circle, the slot pairs 44p are arranged at approximately equal intervals. This slot plate 44 is provided on the upper surface 18u of the dielectric window 18.

[0025] Figure 3 is a plan view showing an example of a dielectric window, and Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. As shown in Figures 3 and 4, the dielectric window 18 is a roughly disc-shaped member made of a dielectric material such as quartz. A through hole 18h is formed in the center of the dielectric window 18. The upper part of the through hole 18h is a space 18s in which the injector 50b of the central introduction section 50, which will be described later, is housed, and the lower part is a gas outlet 18i of the central introduction section 50, which will be described later. The central axis of the dielectric window 18 coincides with axis Z.

[0026] The surface opposite to the upper surface 18u of the dielectric window, i.e., the lower surface 18b, is in contact with the processing space S and is the surface on which the plasma is generated. This lower surface 18b defines various shapes. Specifically, the lower surface 18b has a flat surface 180 in the central region surrounding the gas outlet 18i. This flat surface 180 is a flat surface perpendicular to the axis Z. The lower surface 18b defines an annular first recess 181. The first recess 181 is annular in the radially outer region of the flat surface 180 and tapers inward toward the thickness direction of the dielectric window 18.

[0027] Furthermore, the lower surface 18b defines a plurality of second recesses 182. These plurality of second recesses 182 are recessed inward in the thickness direction from the flat surface 180. In the example shown in Figures 3 and 4, there are seven plurality of second recesses 182. These plurality of second recesses 182 are formed at equal intervals along the circumferential direction. In addition, the plurality of second recesses 182 have a circular planar shape in a plane perpendicular to the axis Z.

[0028] Figure 5 is a plan view showing the dielectric window 18 as viewed from below, with the slot plate shown in Figure 2 placed on the dielectric window shown in Figure 3. As shown in Figure 5, in a plan view, that is, in the direction of the axis Z, the slot pairs 44p arranged along the radially outer concentric circles overlap the first recess 181. Also, the slot holes 44b of the slot pairs 44p arranged along the radially inner concentric circles overlap the first recess 181. Furthermore, the slot holes 44a of the slot pairs 44p arranged along the radially inner concentric circles overlap the multiple second recesses 182.

[0029] Refer again to Figure 1. In the plasma processing apparatus 10, microwaves generated by the microwave generator 32 are propagated through the coaxial waveguide 16 to the dielectric plate 42 and supplied to the dielectric window 18 through the slot holes 44a and 44b of the slot plate 44. Immediately below the dielectric window 18, the microwave energy is concentrated in the first recess 181 and the second recess 182, which are defined by portions having relatively thin plate thicknesses. Therefore, in this plasma processing apparatus 10, it is possible to generate plasma that is stably distributed in the circumferential and radial directions.

[0030] The plasma processing apparatus 10 also includes a central introduction section 50 and a peripheral introduction section 52. The central introduction section 50 includes a conduit 50a, an injector 50b, and a gas outlet 18i. The conduit 50a is passed through the inner bore of the inner conductor 16b of the coaxial waveguide 16. The end of the conduit 50a extends into the space 18s (see Figure 4) defined by the dielectric window 18 along the axis Z. The injector 50b is housed in this space 18s and below the end of the conduit 50a. The injector 50b is provided with a plurality of through holes extending in the direction of the axis Z. The dielectric window 18 also provides the gas outlet 18i described above. The gas outlet 18i is continuous below the space 18s and extends along the axis Z. In this configuration, the central introduction unit 50 supplies gas to the injector 50b via the conduit 50a, and discharges the gas from the injector 50b via the gas discharge port 18i. In this way, the central introduction unit 50 discharges the gas directly below the dielectric window 18 along the axis Z. That is, the central introduction unit 50 introduces the gas into the plasma generation region where the electron temperature is high. Furthermore, the gas discharged from the central introduction unit 50 flows generally along the axis Z towards the central region of the substrate W.

[0031] In one embodiment, the plasma processing apparatus 10 includes a first gas supply unit 71 configured to supply gas into the chamber 12. The first gas supply unit 71 is connected to the central introduction unit 50. The first gas supply unit 71 includes a first flow rate control unit group FCG1 and a first gas source group GSG1. The first gas source group GSG1 is connected to the central introduction unit 50 via the first flow rate control unit group FCG1. The first gas source group GSG1 includes a plurality of first gas sources. The plurality of first gas sources include sources for each of the plurality of gases used in the plasma processing method described later. The plurality of gases used in the plasma processing method include one or more gases that constitute the processing gas and noble gases such as argon (Ar) gas. The processing gas may also be a cleaning gas. The cleaning gas includes, for example, sulfur hexafluoride (SF6) gas and oxygen (O2) gas. The first flow rate control unit group FCG1 includes a plurality of flow controllers and a plurality of on-off valves. Each first gas source is connected to the central inlet 50 via the corresponding flow controller and on / off valve of the first flow control unit group FCG1.

[0032] The peripheral introduction section 52 is located between the gas outlet 18i of the central introduction section 50 and the upper surface of the substrate support section 20 in the height direction, i.e., the axial Z direction. The peripheral introduction section 52 introduces gas into the processing space S from a position along the side wall 12a. This peripheral introduction section 52 includes a plurality of gas outlets 52i. The plurality of gas outlets 52i are arranged along the circumferential direction below the gas outlet 18i and above the substrate support section 20.

[0033] The peripheral introduction section 52 includes, for example, an annular tube 52p. This tube 52p is positioned, for example, at a distance of 90 mm above the upper surface of the substrate support section 20. Multiple gas outlets 52i are formed in this tube 52p. The annular tube 52p may be made of, for example, quartz. As shown in Figure 1, in one embodiment, the annular tube 52p is in contact with the side wall 12a.

[0034] In one embodiment, the plasma processing apparatus 10 includes a second gas supply unit 72 configured to supply gas into the chamber 12. The annular pipe 52p of the peripheral introduction unit 52 is connected to the second gas supply unit 72. The second gas supply unit 72 includes a second flow control unit group FCG2 and a second gas source group GSG2. The annular pipe 52p of the peripheral introduction unit 52 is connected to the second gas source group GSG2 via a gas supply block 62 and the second flow control unit group FCG2. The second gas source group GSG2 includes the same multiple gas sources as the first gas source group GSG1. The second flow control unit group FCG2 includes multiple flow controllers and multiple on-off valves. Each second gas source is connected to the peripheral introduction unit 52 via the corresponding flow controller and on-off valve of the second flow control unit group FCG2.

[0035] In this plasma processing apparatus 10, the type of gas introduced into the processing space S from the central introduction section 50 and the flow rate of one or more gases introduced into the processing space S from the central introduction section 50 can be independently controlled. Furthermore, in this plasma processing apparatus 10, the type of gas introduced into the processing space S from the peripheral introduction section 52 and the flow rate of one or more gases introduced into the processing space S from the peripheral introduction section 52 can be independently controlled.

[0036] As shown in Figure 1, the plasma processing apparatus 10 may further include a control unit Cnt. The control unit Cnt may be a controller such as a programmable computer. The control unit Cnt may control various parts of the plasma processing apparatus 10 according to a recipe and program. For example, the control unit Cnt may send control signals to the flow controllers and on-off valves of the first flow control unit group FCG1 to adjust the type of gas and the flow rate of gas introduced from the central introduction unit 50. The control unit Cnt may also send control signals to the flow controllers and on-off valves of the second flow control unit group FCG2 to adjust the type of gas and the flow rate of gas introduced from the peripheral introduction unit 52. Furthermore, the control unit Cnt may supply control signals to the microwave generator 32, the high-frequency power supply RFG, and the exhaust system 30 to control the microwave power, the power and ON / OFF of the high-frequency bias power, and the pressure in the chamber 12. In addition, the control unit Cnt may send control signals to the heater power supplies connected to the heaters HT, HS, HC, and HE to adjust their temperatures.

[0037] The following describes a plasma processing method according to one exemplary embodiment. Figure 6 is a flowchart of the plasma processing method according to one exemplary embodiment. The operation of the plasma processing apparatus 10 in the plasma processing method shown in Figure 6 will also be described below. In each step of the plasma processing method shown in Figure 6, each part of the plasma processing apparatus 10 can be controlled by the control unit Cnt.

[0038] In the plasma treatment method shown in Figure 6, the plasma treatment is performed when no object such as a substrate W is placed on the substrate support surface MR of the substrate support section 20. This plasma treatment is, for example, cleaning the surface inside the chamber 12. If an object such as a substrate W is placed on the substrate support surface MR before the plasma treatment method is executed, the object is transported out of the treatment space S by a transport device.

[0039] The plasma treatment method shown in Figure 6 includes steps S1 to S3. In step S1, gas is supplied into the chamber 12. The gas supplied into the chamber 12 in step S1 is a noble gas, such as argon. The gas supplied into the chamber 12 in step S1 may consist only of a noble gas. In step S1, the gas is supplied by a first gas supply unit 71 and / or a second gas supply unit 72. During the period in which each step of the plasma treatment method shown in Figure 6 is performed, the pressure inside the chamber 12 is set to a specified pressure by the exhaust device 30.

[0040] Step S2 is performed while gas (e.g., noble gas) is continuously supplied into the chamber 12 from step S1. In step S2, a voltage is applied to the lower electrode of the substrate support 20. Specifically, a voltage from a DC power supply DCS is applied to the chuck electrode CE of the substrate support 20, which serves as the lower electrode. Alternatively, high-frequency bias power from a high-frequency power supply RFG may be supplied to the base LE, which serves as the lower electrode. In step S2, the electron density in the chamber 12 increases. Note that the lower electrode to which high-frequency bias power from the high-frequency power supply RFG is supplied may be any other electrode in the substrate support 20.

[0041] Next, step S3 is performed. In step S3, plasma is generated in the chamber 12. Figure 7 is a flowchart detailing step S3 according to one exemplary embodiment. In one embodiment, step ST3 may include steps S11 to S14, as shown in Figure 7.

[0042] In step S11, while gas (e.g., noble gas) continues to be supplied into the chamber 12 from step S1, microwaves are supplied into the chamber 12 as high-frequency waves. As a result, plasma is ignited in the chamber 12 in step S11. The microwaves are generated by the microwave generator 32 and introduced into the chamber 12 from the antenna 14. The supply of microwaves in step S11 is started, for example, after the voltage applied in step S2 has stabilized. The supply of microwaves in step S11 may start approximately 1 second after the application of voltage to the lower electrode in step S2 begins. Alternatively, the supply of microwaves in step S11 may be performed approximately 0.1 seconds after it is confirmed that the voltage applied to the lower electrode in step S2 has stabilized. The supply of microwaves in step S11 ignites the plasma in the chamber 12.

[0043] Next, step S12 is performed. In step S12, the application of voltage to the lower electrode is stopped. Specifically, if a voltage is being applied to the chuck electrode CE of the substrate support part 20 from the DC power supply DCS, the application of voltage by the DC power supply DCS is stopped. If high-frequency bias power is being supplied to the base LE from the high-frequency power supply RFG, the supply of high-frequency bias power by the high-frequency power supply RFG is stopped. Step S12 is performed, for example, about 1 second after the start of microwave supply in step S11.

[0044] Next, process S13 is performed. In process S13, plasma is generated in the chamber 12 from a mixed gas of noble gas and processing gas. The processing gas is, for example, the cleaning gas described above. The noble gas is supplied into the chamber 12 in process S13 as well, continuing from process S1. In process S13, the processing gas is further supplied into the chamber 12. This mixed gas is supplied by the first gas supply unit 71 and / or the second gas supply unit 72.

[0045] Furthermore, in step S13, microwaves are introduced into the chamber 12 as high-frequency waves while maintaining the plasma generated in step S11. The microwaves are generated by the microwave generator 32 and introduced into the chamber 12 from the antenna 14. As a result, plasma is generated from the mixed gas in the chamber 12.

[0046] Next, step S14 is performed. In step S14, the processing gas is continuously supplied to the chamber 12 from step S13, and high-frequency (microwave) energy is supplied into the chamber 12, at which point the supply of noble gas into the chamber 12 is stopped. In this plasma processing method, for example, the plasma generated from the cleaning gas in steps S13 and S14 is used to clean the surface inside the chamber 12.

[0047] In the plasma processing method and plasma processing apparatus 10 described above, high frequency (microwaves) are supplied while the electron density in the chamber 12 is increased by applying a voltage to the lower electrode. As a result, the time required for plasma ignition after the start of high frequency (microwave) supply is shortened, and the variation in the time required for plasma ignition is reduced. Therefore, in plasma processing performed when no object is placed on the substrate support surface MR of the substrate support section 20, it is possible to shorten the time required for plasma ignition and reduce its variation. It is presumed that the reason why the electron density in the chamber 12 increases when a voltage is applied to the lower electrode is that charged particles such as ions present in the chamber 12 are drawn into the substrate support section 20, and secondary electrons are emitted from the substrate support section 20.

[0048] Furthermore, according to the plasma processing method and plasma processing apparatus 10, plasma is generated from the processing gas (e.g., cleaning gas) in step S13 while the plasma generated from the noble gas is maintained. Therefore, it is possible to easily generate plasma from the processing gas.

[0049] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0050] In another embodiment, the plasma processing apparatus may be a plasma processing apparatus separate from the plasma processing apparatus 10, which uses microwaves to excite a gas. In yet another embodiment, the plasma processing apparatus may be a plasma processing apparatus of a different type than the type that uses microwaves to excite a gas. For example, the plasma processing apparatus may be a capacitively coupled plasma processing apparatus or an inductively coupled plasma processing apparatus. The high-frequency source of such other types of plasma processing apparatus may be configured to generate high-frequency power in the HF frequency band as the high frequency.

[0051] Furthermore, the plasma processing apparatus may be equipped with a bias power supply electrically coupled to the base LE instead of a high-frequency power supply RFG. The bias power supply may be configured to periodically apply voltage pulses to the base LE or other electrodes of the substrate support portion 20.

[0052] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E16] below.

[0053] [E1] A plasma treatment method performed in a plasma processing apparatus, (a) A step of applying a voltage to the lower electrode of a substrate support while gas is supplied into the chamber of the plasma processing apparatus, wherein the substrate support is provided inside the chamber, and (b) A step of generating plasma by supplying high frequency after the application of the voltage to the lower electrode in (a) above, Includes, The above (a) and (b) are plasma processing methods performed when no object is placed on the substrate support surface of the substrate support portion.

[0054] In embodiment E1, high-frequency current is supplied while the electron density in the chamber is increased by applying a voltage to the lower electrode. As a result, the time required for plasma ignition after the start of high-frequency current supply is shortened, and the variation in the time required for plasma ignition is reduced. Therefore, according to embodiment E1, in plasma processing performed when no object is placed on the substrate support surface of the substrate support, it is possible to shorten the time required for plasma ignition and reduce its variation.

[0055] [E2] The above (b) is, (b-1) A step of igniting the plasma by supplying the high frequency while the noble gas is supplied into the chamber, (b-2) A step of generating plasma from a mixed gas of the noble gas and a cleaning gas by supplying the high frequency while maintaining the plasma generated from the noble gas, including, Plasma treatment method as described in E1.

[0056] According to embodiment E2, it is possible to generate a plasma of a mixed gas containing a cleaning gas while maintaining the ignited plasma.

[0057] [E3] The plasma treatment method according to E2, wherein the application of the voltage to the lower electrode is stopped after (b-1) and before (b-2).

[0058] [E4] The above (b) is, (b-3) After (b-2) above, the supply of the noble gas is stopped and the plasma is generated from the cleaning gas, The plasma treatment method described in E2 or E3 is further included.

[0059] [E5] The lower electrode is a bias electrode, In order to apply the voltage to the lower electrode, high-frequency bias power is supplied to the lower electrode, or a voltage pulse is periodically applied to the lower electrode. A plasma treatment method described in any one of items E1 to E4.

[0060] [E6] The substrate support portion further includes an electrostatic chuck, The electrostatic chuck includes a chuck electrode, In order to apply the voltage to the lower electrode, a DC voltage is applied to the chuck electrode. A plasma treatment method described in any one of items E1 to E4.

[0061] [E7] A plasma processing method according to any one of E1 to E6, wherein the aforementioned high frequency is a microwave or high-frequency power in the HF frequency band.

[0062] [E8] The plasma processing method according to any one of E1 to E7, wherein the high frequency is a microwave introduced into the chamber from a radial line slot antenna.

[0063] [E9] Chamber and, A gas supply unit configured to supply gas into the chamber, A substrate support portion, including a lower electrode, is provided within the chamber, A high-frequency generator configured to generate high frequency in order to generate plasma from gas in the chamber, A power supply electrically connected to the lower electrode, Equipped with, The power supply is configured to apply a voltage to the lower electrode when no object is placed on the substrate support surface of the substrate support unit and gas is being supplied into the chamber from the gas supply unit. The high-frequency generator is configured to supply the high frequency to generate plasma after the application of the voltage to the lower electrode has started while no object is placed on the substrate support surface. Plasma processing equipment.

[0064] In the E9 embodiment, high-frequency current is supplied while the electron density in the chamber is increased by applying a voltage to the lower electrode. As a result, the time required for plasma ignition after the start of high-frequency current supply is shortened, and the variation in the time required for plasma ignition is reduced. Therefore, according to the E9 embodiment, in plasma processing performed when no object is placed on the substrate support surface of the substrate support, it is possible to shorten the time required for plasma ignition and reduce its variation.

[0065] [E10] The aforementioned high-frequency source is With the noble gas being supplied into the chamber from the gas supply unit, the plasma is ignited by supplying the high frequency. By supplying the high frequency while maintaining the plasma generated from the noble gas, plasma is generated from the mixed gas of the noble gas and cleaning gas supplied from the gas supply unit. A plasma processing apparatus as described in E9, configured as follows.

[0066] According to the E10 embodiment, it is possible to generate a plasma of a mixed gas containing a cleaning gas while maintaining the ignited plasma.

[0067] [E11] The plasma apparatus according to E10, wherein the power supply is configured to stop applying the voltage to the lower electrode after the plasma has been ignited from the noble gas and before the plasma has been generated from the mixture of the noble gas and the cleaning gas.

[0068] [E12] The gas supply unit is configured to stop supplying the noble gas after the plasma has been generated from the mixed gas. The aforementioned high-frequency generator is configured to generate plasma from the cleaning gas by supplying the high frequency after the supply of the noble gas has been stopped. A plasma processing apparatus as described in E10 or E11.

[0069] [E13] The lower electrode is a bias electrode, The power supply is configured to either supply high-frequency bias power to the lower electrode or periodically apply voltage pulses to the lower electrode in order to apply the voltage to the lower electrode. A plasma processing apparatus as described in any one of items E9 to E12.

[0070] [E14] The substrate support portion further includes an electrostatic chuck, The electrostatic chuck includes a chuck electrode, The power supply is configured to apply a DC voltage to the chuck electrode in order to apply the voltage to the lower electrode. A plasma processing apparatus as described in any one of items E9 to E12.

[0071] [E15] The plasma processing apparatus according to any one of E9 to E14, wherein the high-frequency source is configured to generate microwave or high-frequency power in the HF frequency band as the high frequency.

[0072] [E16] The aforementioned high-frequency source is configured to generate microwaves as the high frequency, The plasma processing apparatus further comprises a radial line slot antenna capable of introducing the microwaves into the chamber. A plasma processing apparatus as described in any one of items E9 to E15.

[0073] From the above description, it will be understood that the various embodiments of this disclosure are described herein for illustrative purposes and can be modified in various ways without departing from the scope and spirit of this disclosure. Accordingly, the various embodiments disclosed herein are not intended to limit the scope and spirit, and the true scope and spirit are shown by the appended claims. [Explanation of Symbols]

[0074] 10...Plasma processing apparatus, 20...Substrate support section, 71...First gas supply section, 72...Second gas supply section, CE...Chuck electrode, Cnt...Control section, DCS...DC power supply, ESC...Electrostatic chuck, LE...Base, MR...Substrate support surface, RFG...High-frequency power supply.

Claims

1. A plasma treatment method performed in a plasma processing apparatus, (a) A step of applying a voltage to the lower electrode of a substrate support while gas is supplied into the chamber of the plasma processing apparatus, wherein the substrate support is provided inside the chamber, and (b) A step of generating plasma by supplying high frequency after the application of the voltage to the lower electrode in (a) above, Includes, The above (a) and (b) are plasma processing methods performed when no object is placed on the substrate support surface of the substrate support portion.

2. The above (b) is, (b-1) A step of igniting the plasma by supplying the high frequency while the noble gas is supplied into the chamber, (b-2) A step of generating plasma from a mixed gas of the noble gas and a cleaning gas by supplying the high frequency while maintaining the plasma generated from the noble gas, including, The plasma treatment method according to claim 1.

3. The plasma processing method according to claim 2, wherein the application of the voltage to the lower electrode is stopped after (b-1) and before (b-2).

4. The above (b) is, (b-3) After (b-2) above, the supply of the noble gas is stopped and the plasma is generated from the cleaning gas, The plasma treatment method according to claim 2 or 3 is further included.

5. The lower electrode is a bias electrode, In order to apply the voltage to the lower electrode, high-frequency bias power is supplied to the lower electrode, or a voltage pulse is periodically applied to the lower electrode. A plasma treatment method according to any one of claims 1 to 3.

6. The substrate support portion further includes an electrostatic chuck, The electrostatic chuck includes a chuck electrode, In order to apply the voltage to the lower electrode, a DC voltage is applied to the chuck electrode. A plasma treatment method according to any one of claims 1 to 3.

7. The plasma processing method according to any one of claims 1 to 3, wherein the high frequency is a microwave or high-frequency power in the HF frequency band.

8. The plasma processing method according to any one of claims 1 to 3, wherein the high frequency is a microwave and is introduced into the chamber from a radial line slot antenna.

9. Chamber and, A gas supply unit configured to supply gas into the chamber, A substrate support portion, including a lower electrode, is provided within the chamber, A high-frequency generator configured to generate high frequency to create plasma from gas in the chamber, A power supply electrically connected to the lower electrode, Equipped with, The power supply is configured to apply a voltage to the lower electrode when no object is placed on the substrate support surface of the substrate support unit and gas is being supplied into the chamber from the gas supply unit. The high-frequency generator is configured to supply the high frequency to generate plasma after the application of the voltage to the lower electrode has started while no object is placed on the substrate support surface. Plasma processing equipment.

10. The aforementioned high-frequency source is With the noble gas being supplied into the chamber from the gas supply unit, the plasma is ignited by supplying the high frequency. By supplying the high frequency while maintaining the plasma generated from the noble gas, plasma is generated from the mixed gas of the noble gas and cleaning gas supplied from the gas supply unit. The plasma processing apparatus according to claim 9, configured as described above.

11. The plasma processing apparatus according to claim 10, wherein the power supply is configured to stop applying the voltage to the lower electrode after the plasma has been ignited from the noble gas and before the plasma has been generated from the mixed gas of the noble gas and the cleaning gas.

12. The gas supply unit is configured to stop supplying the noble gas after the plasma has been generated from the mixed gas. The aforementioned high-frequency generator is configured to generate plasma from the cleaning gas by supplying the high frequency after the supply of the noble gas has been stopped. The plasma processing apparatus according to claim 10 or 11.

13. The lower electrode is a bias electrode, The power supply is configured to either supply high-frequency bias power to the lower electrode or periodically apply voltage pulses to the lower electrode in order to apply the voltage to the lower electrode. A plasma processing apparatus according to any one of claims 9 to 11.

14. The substrate support portion further includes an electrostatic chuck, The electrostatic chuck includes a chuck electrode, The power supply is configured to apply a DC voltage to the chuck electrode in order to apply the voltage to the lower electrode. A plasma processing apparatus according to any one of claims 9 to 11.

15. The plasma processing apparatus according to any one of claims 9 to 11, wherein the high-frequency source is configured to generate microwave or high-frequency power in the HF frequency band as the high frequency.

16. The aforementioned high-frequency source is configured to generate microwaves as the high frequency, The plasma processing apparatus further comprises a radial line slot antenna capable of introducing the microwaves into the chamber. A plasma processing apparatus according to any one of claims 9 to 11.

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