Plasma processing apparatus and plasma processing method

Abstract

A plasma processing apparatus includes a chamber, a substrate support, a high frequency power supply, and a bias power supply. The high frequency power supply supplies high frequency power to a high frequency electrode. The bias power supply applies an electric bias to a bias electrode. An edge ring mounted on the substrate support receives a portion of the electric bias or another electric bias. An outer ring extends radially and outwardly relative to the edge ring and receives a portion of the high frequency power. A power level of the high frequency power is changed in synchronization with the electric bias within each cycle of the electric bias.

Description

Technical Field

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

[0002] A plasma processing apparatus is used for plasma processing of a substrate. The apparatus includes a chamber, an electrostatic chuck, and a lower electrode. The electrostatic chuck and lower electrode are disposed within the chamber. The electrostatic chuck is mounted on the lower electrode. The electrostatic chuck supports an edge ring placed thereon. The edge ring is sometimes referred to as a focusing ring. The electrostatic chuck supports the substrate disposed within the area surrounded by the edge ring. During plasma processing in the apparatus, gas is supplied to the chamber. High-frequency power is supplied to the lower electrode. Plasma is formed from the gas within the chamber. The substrate is processed by chemical species such as ions and free radicals from the plasma.

[0003] If plasma processing is performed, the edge ring will be consumed, and the thickness of the edge ring will decrease. If the thickness of the edge ring decreases, the position of the upper end of the plasma sheath layer (hereinafter referred to as "sheath layer") above the edge ring will become lower. The vertical position of the upper end of the sheath layer above the edge ring should be equal to the vertical position of the upper end of the sheath layer above the substrate. Japanese Patent Application Publication No. 2008-227063 (hereinafter referred to as "Patent Document 1") discloses a plasma processing apparatus capable of adjusting the vertical position of the upper end of the sheath layer above the edge ring. The plasma processing apparatus described in Patent Document 1 is configured to apply a DC voltage to the edge ring. Furthermore, the plasma processing apparatus described in Patent Document 1 is configured to adjust the power level of the high-frequency power supplied to the lower electrode when a DC voltage is applied to the edge ring. Summary of the Invention

[0004] This invention provides a technique for adjusting the thickness of the sheath layer on the edge ring and the radial density distribution of plasma.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, and a bias power supply. The substrate support has a bias electrode. The high-frequency power supply is configured to generate high-frequency power supplied to the high-frequency electrode to generate plasma above a substrate supported by the substrate support within the chamber. The bias power supply is connected to the bias electrode via an electrical path. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to other bias power supplies. An outer ring extends radially and outward relative to the edge ring. The outer ring is electrically connected to the high-frequency power supply in a manner that receives a portion of the high-frequency power. The high-frequency power supply is configured to change the power level of the high-frequency power synchronously with the electrical bias during each cycle of the electrical bias output from the bias power supply to the bias electrode.

[0006] According to an exemplary embodiment, the thickness of the sheath on the edge ring can be adjusted and the density distribution of the plasma in the radial direction can be adjusted. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment.

[0008] Figure 2 (a) and Figure 2 (b) are respectively Figure 1 The timing diagram of high-frequency power and electrical bias used in an example of the plasma processing apparatus shown is illustrated.

[0009] Figure 3 (a) and Figure 3 (b) are respectively Figure 1 The timing diagram of high-frequency power and electrical bias used in another example of the plasma processing apparatus shown is illustrated.

[0010] Figure 4 This is a diagram that schematically illustrates a plasma processing apparatus according to another exemplary embodiment.

[0011] Figure 5 (a) and Figure 5 (b) are respectively Figure 4 The timing diagram of the first high-frequency power, the second high-frequency power, and the electrical bias used in an example of the plasma processing apparatus shown is illustrated.

[0012] Figure 6 (a) and Figure 6 (b) are respectively Figure 4 The timing diagram of the first high-frequency power, the second high-frequency power, and the electrical bias used in another example of the plasma processing apparatus shown is illustrated.

[0013] Figure 7 This is a schematic diagram illustrating a plasma processing apparatus according to yet another exemplary embodiment.

[0014] Figure 8 This is a schematic diagram illustrating a plasma processing apparatus according to yet another exemplary embodiment. Detailed Implementation

[0015] The following describes various exemplary embodiments.

[0016] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, and a bias power supply. The substrate support has a bias electrode. The high-frequency power supply is configured to generate high-frequency power supplied to the high-frequency electrode to generate plasma above a substrate supported by the substrate support within the chamber. The bias power supply is connected to the bias electrode via an electrical path. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to other bias power supplies. An outer ring extends radially and outward relative to the edge ring. The outer ring is electrically connected to the high-frequency power supply in a manner that receives a portion of the high-frequency power. The high-frequency power supply is configured to change the power level of the high-frequency power synchronously with the electrical bias during each cycle of the electrical bias output from the bias power supply to the bias electrode.

[0017] According to the above embodiment, the level of negative bias in the edge ring is adjusted by an impedance regulator or other bias power supply. Therefore, according to the above embodiment, the thickness of the sheath layer on the edge ring can be adjusted. Furthermore, in the above embodiment, the power level of the high-frequency power supplied to the outer ring is varied during each cycle of the electrical bias. Therefore, according to the above embodiment, the radial plasma density distribution can be adjusted during each cycle of the electrical bias.

[0018] In one exemplary embodiment, the plasma processing apparatus may further include a first electrode and a second electrode. The first electrode is electrically coupled to an edge ring. The first electrode may also be capacitively coupled to the edge ring. The second electrode is electrically coupled to an outer ring. The second electrode may also be capacitively coupled to the outer ring. An impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives a portion of the high-frequency power or additional high-frequency power from another high-frequency power source via the second electrode.

[0019] In one exemplary embodiment, the high-frequency power supply may be configured to supply pulses of high-frequency power to the high-frequency electrodes and the outer ring during the same period of each electrical bias cycle.

[0020] In one exemplary embodiment, the aforementioned same period can be a first period in which the electrical bias has a voltage higher than the average voltage of the electrical bias during its cycle, or a second period in which the electrical bias has a voltage lower than the average voltage during its cycle. When a pulse of high-frequency power is supplied to the high-frequency electrode and the outer ring during the first period, the plasma density on the substrate and the plasma density around the outer ring can be increased. Furthermore, when a pulse of high-frequency power is supplied to the high-frequency electrode and the outer ring during the second period, the plasma density around the outer ring can be relatively increased relative to the plasma density on the substrate.

[0021] In one exemplary embodiment, the substrate support may have a base and an electrostatic chuck disposed on the base.

[0022] In one exemplary embodiment, the base plate may provide a lower electrode as a bias electrode. The lower electrode may be a high-frequency electrode. A high-frequency power supply may be electrically connected to the lower electrode via the aforementioned electrical path.

[0023] In one exemplary embodiment, the plasma processing apparatus may further include an impedance regulator. This impedance regulator provides variable impedance between the aforementioned electrical path and the outer ring, or between the lower electrode and the outer ring.

[0024] In one exemplary embodiment, the plasma processing apparatus may further include a filter connected between the impedance regulator and the second electrode, the impedance regulator providing variable impedance between the electrical path and the outer ring or between the lower electrode and the outer ring. The filter may have frequency characteristics that selectively pass high-frequency power through an electrical bias supplied from a bias power supply to the lower electrode.

[0025] In one exemplary embodiment, a bias electrode may be disposed in an electrostatic chuck. A base may provide a lower electrode as a high-frequency electrode. A high-frequency power supply may be electrically connected to the lower electrode. In one exemplary embodiment, the plasma processing apparatus may further include an impedance regulator that provides variable impedance between the electrical path connecting the high-frequency power supply to the lower electrode and the outer ring, or between the lower electrode and the outer ring.

[0026] In another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a first high-frequency power supply, a bias power supply, and a second high-frequency power supply. The substrate support has a bias electrode. The first high-frequency power supply generates a first high-frequency power supplied to the high-frequency electrode to generate plasma above a substrate supported by the substrate support within the chamber. The bias power supply is connected to the bias electrode via an electrical path. The second high-frequency power supply is configured to generate a second high-frequency power supplied to an outer ring. The outer ring extends radially and outward relative to an edge ring mounted on the substrate support. The edge ring is electrically connected to the bias power supply, or to other bias power supplies, via an impedance regulator that provides variable impedance between the bias electrode and the edge ring, or between the electrical path and the edge ring. The second high-frequency power supply is configured to synchronously change the power level of the second high-frequency power supply during each cycle of an electrical bias output from the bias power supply to the bias electrode.

[0027] According to the above embodiment, the level of negative bias in the edge ring is adjusted by an impedance regulator or other bias power supply. Therefore, according to the above embodiment, the thickness of the sheath layer on the edge ring can be adjusted. Furthermore, in the above embodiment, the power level of the second high-frequency power supplied to the outer ring in each cycle of electrical bias is changed. Therefore, according to the above embodiment, the radial plasma density distribution can be adjusted in each cycle of electrical bias.

[0028] In one exemplary embodiment, the plasma processing apparatus may further include a first electrode and a second electrode. The first electrode is electrically coupled to an edge ring. The first electrode may also be capacitively coupled to the edge ring. The second electrode is electrically coupled to an outer ring. The second electrode may also be capacitively coupled to the outer ring. An impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives a second high-frequency power via the second electrode.

[0029] In one exemplary embodiment, the substrate support may have a base and an electrostatic chuck disposed on the base.

[0030] In one exemplary embodiment, the base plate may provide a lower electrode as a bias electrode. The lower electrode may be a high-frequency electrode. A high-frequency power supply may be electrically connected to the lower electrode via the aforementioned electrical path.

[0031] In one exemplary embodiment, a bias electrode may be disposed in an electrostatic chuck. A base may be provided as a lower electrode serving as a high-frequency electrode. A first high-frequency power supply may be electrically connected to the lower electrode.

[0032] In one exemplary embodiment, the second high-frequency power supply may be configured to supply pulses of the second high-frequency power to the outer ring during the same period in each cycle of electrical bias.

[0033] In one exemplary embodiment, each cycle of the electrical bias includes a first period in which the electrical bias has a voltage greater than the average voltage of the electrical bias within the cycle, or a second period in which the electrical bias has a voltage lower than the average voltage within the cycle. The same period can be the first period. In this embodiment, the radial plasma density distribution is adjusted by the ratio of the second high-frequency power supplied to the outer ring and the first high-frequency power supplied to the high-frequency electrodes during the period when the sheath layer on the substrate is thin.

[0034] In one exemplary embodiment, the first high-frequency power source may supply a continuous wave of the first high-frequency power during both the first and second periods, or it may supply a pulse of the first high-frequency power during the second period.

[0035] In one exemplary embodiment, the first high-frequency power source may supply pulses of the first high-frequency power during the first period.

[0036] In one exemplary embodiment, the outer ring may extend in a manner that surrounds the edge ring.

[0037] In one exemplary embodiment, the bias power supply may be configured to supply high-frequency bias power to the bias electrode, or to periodically apply a pulsed voltage or a voltage with arbitrary waveform to the lower electrode. The pulsed voltage may be negative. The pulsed voltage may be a pulsed, negative-polarity DC voltage.

[0038] In another exemplary embodiment, a plasma processing method is provided. The plasma processing method includes a step (a1) of supplying high-frequency power from a high-frequency power source to a high-frequency electrode in order to generate plasma above a substrate supported by a substrate support within a cavity of a plasma processing apparatus. The plasma processing method further includes a step (b1) of applying an electrical bias from a bias power source to a bias electrode of the substrate support. The plasma processing apparatus includes a cavity, a substrate support, a high-frequency power source, and a bias power source connected to the bias electrode via an electrical path. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power source via an impedance regulator that provides a variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to other bias power sources. An outer ring extends radially and outward relative to the edge ring. The outer ring is electrically connected to the high-frequency power source in a manner that receives a portion of the high-frequency power. In step (a1), the high-frequency power source changes the power level of the high-frequency power source synchronously with the electrical bias during each cycle of the electrical bias output from the bias power source to the bias electrode.

[0039] In one exemplary embodiment, in step (a1), the high-frequency power supply can supply pulses of high-frequency power to the high-frequency electrode and the outer ring during the same period of each cycle of the electrical bias. The same period can be a first period in which the electrical bias has a voltage higher than the average voltage of the electrical bias during its cycle, or a second period in which the electrical bias has a voltage lower than the average voltage during its cycle.

[0040] In another exemplary embodiment, a plasma processing method is provided. The plasma processing method includes a step (a2) of supplying a first high-frequency power from a first high-frequency power source to a high-frequency electrode in order to generate plasma above a substrate supported by a substrate support within a chamber of a plasma processing apparatus. The plasma processing method further includes a step (b2) of applying an electrical bias from a bias power source to a bias electrode of the substrate support. The plasma processing method further includes a step (c2) of supplying a second high-frequency power from a second high-frequency power source to an outer ring. The plasma processing apparatus includes a chamber, a substrate support, a first high-frequency power source, a bias power source connected to the bias electrode via an electrical path, and a second high-frequency power source. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power source via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to other bias power sources. The outer ring extends radially and outward relative to the edge ring. In step (c2), the second high-frequency power source changes the power level of the second high-frequency power source synchronously with the electrical bias during each cycle of the electrical bias.

[0041] In one exemplary embodiment, in step (c2), the second high-frequency power supply can supply pulses of the second high-frequency power to the outer ring during the same period of each cycle of the electrical bias. Each cycle of the electrical bias can include a first period in which the electrical bias has a voltage higher than the average voltage of the electrical bias during its cycle, or a second period in which the electrical bias has a voltage lower than the average voltage during its cycle. The same period can be the first period.

[0042] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent parts are labeled with the same symbols.

[0043] Figure 1 This is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment. Figure 1 The plasma processing apparatus 1 shown is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. An internal space 10s is provided within the chamber 10. The central axis of the internal space 10s is an axis AX extending in the vertical direction.

[0044] In one embodiment, the chamber 10 may include a chamber body 12. The chamber body 12 has a generally cylindrical shape. An internal space 10s is disposed within the chamber body 12. The chamber body 12 is made of, for example, aluminum. The chamber body 12 is electrically grounded. A plasma-resistant membrane is formed on the inner wall surface of the chamber body 12, i.e., the wall surface dividing the internal space 10s. This membrane may be a ceramic membrane formed by anodizing or by forming a yttrium oxide membrane.

[0045] The sidewall of the chamber body 12 is provided with a passage 12p. When the substrate W is transported between the internal space 10s and the outside of the chamber 10, the substrate W passes through the passage 12p. A gate valve 12g is provided along the sidewall of the chamber body 12 for opening and closing the passage 12p.

[0046] The plasma processing apparatus 1 also includes a substrate support 16. The substrate support 16 is configured to support a substrate W placed on the substrate support 16 within the chamber 10. The substrate W has a generally disk-shaped form. The substrate W is placed on the substrate support 16 with its center aligned with axis AX. The substrate support 16 is configured to further support an edge ring ER. The edge ring ER has a ring shape. The edge ring ER may be conductive. The edge ring ER is formed, for example, of silicon or silicon carbide. The edge ring ER is mounted on the substrate support 16 with its central axis aligned with axis AX. The substrate W is disposed on the substrate support 16 within the area surrounded by the edge ring ER.

[0047] The substrate support 16 may be surrounded by an insulating portion 17. The insulating portion 17 extends radially relative to the axis AX and circumferentially outside the substrate support 16. The insulating portion 17 is formed of an insulating material such as quartz. The insulating portion 17 can support the substrate support 16.

[0048] The substrate support 16 has a base 18. The substrate support 16 may also have an electrostatic chuck 20. The base 18 and the electrostatic chuck 20 may be disposed in the chamber 10. The base 18 is formed of a conductive material such as aluminum and has a generally disk-shaped form. The central axis of the base 18 is axis AX.

[0049] A flow path 18f is provided in the base 18. Flow path 18f is for heat exchange medium. The heat exchange medium is, for example, a refrigerant. Flow path 18f is connected to a heat exchange medium supply device 22. The supply device 22 is located outside the chamber 10. Flow path 18f receives the heat exchange medium supplied from the supply device 22. The heat exchange medium supplied to flow path 18f flows through flow path 18f back to the supply device 22.

[0050] An electrostatic chuck 20 is disposed on the base 18. When the substrate W is processed in the internal space for 10 seconds, the substrate W is placed on the electrostatic chuck 20 and held by the electrostatic chuck 20.

[0051] The electrostatic chuck 20 has a body and chuck electrodes. The body of the electrostatic chuck 20 is formed of a dielectric such as aluminum oxide or aluminum nitride. The body of the electrostatic chuck 20 has a generally disc-shaped form. The central axis of the electrostatic chuck 20 is axis AX. The chuck electrodes are disposed within the body of the electrostatic chuck 20. The chuck electrodes have a film shape. The chuck electrodes are electrically connected to a DC power supply via a switch. When a voltage from the DC power supply is applied to the chuck electrodes, an electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. Through the generated electrostatic attraction, the substrate W is attracted to the electrostatic chuck 20 and held by the electrostatic chuck 20.

[0052] The electrostatic chuck 20 includes a substrate placement area. The substrate placement area is a region having a generally disk-shaped structure. The central axis of the substrate placement area is axis AX. When processing the substrate W within the chamber 10, the substrate W is placed on the upper surface of the substrate placement area.

[0053] In one embodiment, the electrostatic chuck 20 may further include an edge ring mounting region. The edge ring mounting region extends circumferentially such that it surrounds the substrate mounting region around the central axis of the electrostatic chuck 20. An edge ring ER is mounted on the upper surface of the edge ring mounting region. The edge ring ER may be partially mounted on the insulating portion 17.

[0054] The plasma processing apparatus 1 may also provide a gas supply line 24. The gas supply line 24 supplies heat transfer gas, such as He gas, from the gas supply mechanism to the gap between the upper surface of the electrostatic chuck 20 and the back (lower surface) of the substrate W.

[0055] The plasma processing apparatus 1 also includes an upper electrode 30. The upper electrode 30 is disposed above the substrate support 16. The upper electrode 30, together with the component 32, seals the upper opening of the chamber body 12. The component 32 is insulating. The upper electrode 30 is supported on the upper part of the chamber body 12 via the component 32.

[0056] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 divides an internal space 10s. The top plate 34 provides a plurality of vent holes 34a. The plurality of vent holes 34a penetrate the top plate 34 along its thickness direction (vertical direction). The top plate 34 is formed of silicon, for example. Alternatively, the top plate 34 may have a structure in which a plasma-resistant film is formed on the surface of an aluminum component. This film may be a ceramic film formed by anodizing or formed of yttrium oxide.

[0057] The support body 36 detachably supports the top plate 34. The support body 36 is formed of a conductive material, for example, aluminum. A gas diffusion chamber 36a is provided within the support body 36. The support body 36 also provides a plurality of gas holes 36b. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a and communicate with a plurality of exhaust holes 34a respectively. The support body 36 also provides a gas inlet port 36c. The gas inlet port 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet port 36c.

[0058] A gas source group 40 is connected to the gas supply pipe 38 via a valve group 41, a flow controller group 42, and a valve group 43. The gas supply unit comprises the gas source group 40, valve group 41, flow controller group 42, and valve group 43. The gas source group 40 includes multiple gas sources. Valve groups 41 and 43 each include multiple valves (e.g., open and close valves). The flow controller group 42 includes multiple flow controllers. These multiple flow controllers are either mass flow controllers or pressure-controlled flow controllers. The multiple gas sources of the gas source group 40 are connected to the gas supply pipe 38 via valves corresponding to valve group 41, flow controllers corresponding to flow controller group 42, and valves corresponding to valve group 43. The plasma processing apparatus 1 can supply gas from one or more selected gas sources from the multiple gas sources of the gas source group 40 to the internal space for 10 seconds at individually adjustable flow rates.

[0059] The plasma processing apparatus 1 may also include a baffle member 48. The baffle member 48 extends between the insulating portion 17 and the sidewall of the chamber body 12. The baffle member 48 may be constructed, for example, by coating an aluminum component with a ceramic such as yttrium oxide. The baffle member 48 is provided with a plurality of through holes. The space above the baffle member 48 and the space below the baffle member 48 are connected via the plurality of through holes.

[0060] The plasma processing apparatus 1 may also include an exhaust device 50. The exhaust device 50 is located below the baffle member 48 and is connected to the bottom of the chamber body 12 via an exhaust pipe 52. The exhaust device 50 has a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbomolecular pump, which can reduce the pressure in the internal space by 10s.

[0061] The plasma processing apparatus 1 also includes a high-frequency power supply 61. The high-frequency power supply 61 generates high-frequency power HF supplied to a high-frequency electrode in order to generate plasma above the substrate W supported by the substrate support 16. The high-frequency power HF has a first frequency. The first frequency is in the range of 27 to 100 MHz, for example, a frequency of 40 MHz or 60 MHz. In one embodiment, the high-frequency electrode is a base 18. That is, in one embodiment, the base 18 is provided with a lower electrode as a high-frequency electrode. The high-frequency power supply 61 is connected to the base 18 via an integrator 63. The integrator 63 has an integration circuit configured to integrate the impedance of the load side (base 18 side) of the high-frequency power supply 61 with the output impedance of the high-frequency power supply 61. In one embodiment, the high-frequency power supply 61 may be connected to the base 18 via the integrator 63 and an electrical path 71. In one embodiment, the electrical path 71 connects a bias power supply 62 to the base 18. That is, in one embodiment, the base 18 is provided with a lower electrode as a bias electrode.

[0062] The bias power supply 62 is configured as a bias electrode for the substrate support 16. Figure 1 In the example, an electrical bias EB is applied to the base 18. The electrical bias EB can be used to introduce ions into the substrate W.

[0063] In one embodiment, the bias power supply 62 can generate high-frequency bias power as an electrical bias EB. The high-frequency bias power has a second frequency. This second frequency is different from the frequency of the high-frequency power HF. The second frequency can be lower than the first frequency. The second frequency is a frequency in the range of 50 kHz to 27 MHz, for example, 400 kHz. Furthermore, when the high-frequency power supply 61 is connected to the upper electrode 30 instead of the base 18, the second frequency can be lower than the first frequency, higher than the first frequency, or the same as the first frequency.

[0064] In order to supply high-frequency bias power to the bias electrode, the bias power supply 62 connects to the bias electrode via the integrator 64. Figure 1 In the example, base station 18 is connected. Integrator 64 has an integration circuit configured to integrate the impedance on the load side of bias power supply 62 with the output impedance of bias power supply 62.

[0065] In another embodiment, the bias power supply 62 may be configured to periodically supply bias electrodes as an electrical bias EB. Figure 1In this example, a voltage pulse (i.e., a pulsed voltage) or a voltage with an arbitrary waveform is applied to the base 18. The voltage pulse can have a negative polarity. The voltage pulse can also be a negative DC voltage pulse. The voltage pulse is applied to the base 18 at a period specified in the second frequency. In this embodiment, the second frequency can be a frequency in the range of 1 kHz to 1 MHz. The voltage of the pulse can vary during the period during which the pulse is applied to the bias electrode.

[0066] In one embodiment, the plasma processing apparatus 1 may further include a first electrode 81. The first electrode 81 is electrically coupled to the edge ring ER. The first electrode 81 may also be capacitively coupled to the edge ring ER. The first electrode 81 is disposed below the edge ring ER. In one embodiment, the first electrode 81 may be disposed within the edge ring mounting region of the electrostatic chuck 20. In another embodiment, the first electrode 81 may be disposed in the insulating portion 17. Alternatively, the first electrode 81 may be directly coupled to the edge ring ER. The first electrode 81 may be a single electrode or may extend circumferentially around the axis AX. Alternatively, the first electrode 81 may also include a plurality of electrodes arranged circumferentially around the axis AX. The plurality of electrodes constituting the first electrode 81 may be arranged at equal intervals.

[0067] In one embodiment, the plasma processing apparatus 1 may further include an impedance regulator 83. The impedance regulator 83 provides a variable impedance. The variable impedance of the impedance regulator 83 can be controlled by the control unit MC, described later. In one embodiment, the impedance regulator 83 is connected to a high-frequency electrode ( Figure 1 In the example, this is between the base 18 and the first electrode 81. In one embodiment, the impedance regulator 83 includes one or more variable impedance elements. The one or more variable impedance elements may include variable capacitance capacitors. In another embodiment, the impedance regulator 83 may include a circuit formed by parallel connection of multiple series circuits. The multiple series circuits may each include a series connection of a fixed impedance element and a switching element. The fixed impedance element is, for example, a fixed capacitance capacitor.

[0068] In one embodiment, the plasma processing apparatus 1 may further include a second electrode 82. The second electrode 82 is electrically coupled to the outer ring OR. The second electrode 82 may also be capacitively coupled to the outer ring OR. The outer ring OR has a ring shape. The outer ring OR may be conductive. The outer ring OR is formed, for example, of silicon or silicon carbide. The outer ring OR extends radially and outward relative to the edge ring ER. The outer ring OR is arranged such that its axis AX aligns with its central axis. In one embodiment, the outer ring OR extends to surround the edge ring ER. The outer ring OR may be mounted on a substrate support 16 or an insulating portion 17.

[0069] like Figure 1As shown, the second electrode 82 can be disposed below the outer ring OR. The second electrode 82 can be disposed in or on the surface of the insulating portion 17. Alternatively, the second electrode 82 can be directly coupled to the outer ring OR. The second electrode 82 can be a single electrode or extend circumferentially around the axis AX. Alternatively, the second electrode 82 can also include multiple electrodes arranged circumferentially around the axis AX. The multiple electrodes constituting the second electrode 82 can be arranged at equal intervals.

[0070] In the plasma processing apparatus 1, a portion of high-frequency power HF is supplied to the outer ring OR. In one embodiment, a portion of the high-frequency power HF is supplied to the outer ring OR via a second electrode 82. The outer ring OR is connected to the electrical path 71 via an impedance regulator 84. In one embodiment, the second electrode 82 is connected to the electrical path 71 via the impedance regulator 84. That is, the impedance regulator 84 is connected between the electrical path 71 and the second electrode 82. The impedance regulator 84 provides a variable impedance. The variable impedance of the impedance regulator 84 can be controlled by a control unit MC. In one embodiment, the impedance regulator 84 includes one or more variable impedance elements. The one or more variable impedance elements may include variable capacitance capacitors. In another embodiment, the impedance regulator 84 may include a circuit formed by parallel connection of multiple series circuits. The multiple series circuits may each include a series connection of a fixed impedance element and a switching element. The fixed impedance element is, for example, a fixed capacitance capacitor.

[0071] In one embodiment, the plasma processing apparatus 1 may further include a control unit MC. The control unit MC is a computer equipped with a processor, storage device, input device, display device, etc., and controls each part of the plasma processing apparatus 1. Specifically, the control unit MC executes a control program stored in the storage device and controls each part of the plasma processing apparatus 1 based on process data stored in the storage device. Through the control of the control unit MC, the program specified by the process data is executed in the plasma processing apparatus 1.

[0072] In one embodiment, the electrical path 71 can be configured to uniformly distribute power to the base station 18 circumferentially relative to the axis AX. In another embodiment, the electrical path 71 may include multiple branch lines respectively connected to multiple locations on the base station 18. The multiple locations are equidistant from the axis AX and are arranged at equal intervals circumferentially relative to the axis AX. Furthermore, the multiple branch lines of the electrical path 71 are arranged at equal intervals circumferentially relative to the axis AX. Additionally, the electrical lengths of the electrical path 71 relative to each of the multiple locations on the base station 18 are approximately equal. According to this embodiment, the base station 18 can be uniformly powered via the electrical path 71.

[0073] In one embodiment, the plasma processing apparatus 1 may further include an electrical path 72. The electrical path 72 is distributed at the bias electrode (in... Figure 1 In this example, the electrical path 72 is an electrical path between the base 18 and the edge ring ER (or the first electrode 81) for supplying power to the first electrode 81. The electrical path 72 may include multiple branch lines connected to multiple locations on the edge ring ER (or the first electrode 81). These multiple locations are equidistant from the axis AX and are arranged at equal intervals circumferentially relative to the axis AX. Furthermore, the multiple branch lines of the electrical path 72 are arranged at equal intervals circumferentially relative to the axis AX. The electrical lengths of the electrical path 72 relative to each of the multiple locations on the edge ring ER (or the first electrode 81) are approximately equal. According to this embodiment, the edge ring ER can be uniformly powered via the electrical path 72.

[0074] In one embodiment, the plasma processing apparatus 1 may further include an electrical path 73. The electrical path 73 is distributed at the high-frequency electrodes ( Figure 1 In this example, the electrical path 73 is between the base 18 and the outer ring OR (or the second electrode 82) and is used to supply power to the outer ring OR. The electrical path 73 may include multiple branch lines connected to multiple locations on the outer ring OR (or the second electrode 82). These multiple locations are equidistant from the axis AX and are arranged at equal intervals circumferentially relative to the axis AX. Furthermore, the multiple branch lines of the electrical path 73 are arranged at equal intervals circumferentially relative to the axis AX. Also, the electrical lengths of the electrical path 73 relative to the multiple locations on the outer ring OR (or the second electrode 82) are approximately equal to each other. According to this embodiment, power can be uniformly supplied to the outer ring OR via the electrical path 73.

[0075] In one embodiment, the plasma processing apparatus 1 may further include a filter 74. The filter 74 is connected between the impedance regulator 84 and the outer ring OR (or the second electrode 82). The filter 74 may have frequency characteristics that selectively allow high-frequency power HF to pass through the electrical bias EB. Alternatively, the filter 74 may have frequency characteristics that selectively allow the electrical bias EB to pass through the high-frequency power HF. Alternatively, the passband of the filter 74 may be changed to the frequency band of the high-frequency power HF, the frequency band of the electrical bias EB, or any one of both.

[0076] The following, with Figure 1 Let's refer to each other. Figure 2 of (a), Figure 2 (b) Figure 3 (a) and Figure 3 (b) Figure 2 (a) and Figure 2 (b) are respectively Figure 1 The timing diagram of high-frequency power and electrical bias used in an example of the plasma processing apparatus shown is illustrated. Figure 3 (a) and Figure 3 (b) are respectively Figure 1 The following are timing diagrams of high-frequency power and electrical bias used in another example of the plasma processing apparatus shown. These diagrams represent the power level of the high-frequency power HF and the voltage level of the electrical bias EB.

[0077] exist Figure 2 of (a), Figure 2 (b) Figure 3 (a) and Figure 3 In (b), "H" in high-frequency power HF indicates a high power level of high-frequency power HF. "L" in high-frequency power HF indicates a lower power level than indicated by "H". "ON" in high-frequency power HF indicates that high-frequency power HF is being supplied, and "OFF" in high-frequency power HF indicates that the supply of high-frequency power HF is stopped, i.e., the high-frequency power is HF0 (W). Furthermore, "ON" in electrical bias EB indicates that a voltage pulse (e.g., a negative DC voltage pulse) is applied to base station 18. Furthermore, "OFF" in electrical bias EB indicates that the voltage pulse is stopped, i.e., the voltage of electrical bias EB is 0 (V).

[0078] The period CY of the electrical bias EB includes a first period P1 and a second period P2. The first period P1 is the period during which the electrical bias EB has a voltage higher than its average voltage within the period CY. For example, the first period P1 is the period during which the electrical bias EB has a positive or zero voltage. The second period P2 is the period during which the electrical bias EB has a voltage lower than the aforementioned average voltage. For example, the second period P2 is the period during which the electrical bias EB has a negative voltage. Figure 2 (a) and Figure 2 As shown in (b), the electrical bias EB can be a high-frequency bias power. Or, as... Figure 3 (a) and Figure 3 As shown in (b), the electrical bias EB may include pulses of voltage (e.g., pulses of negative DC voltage) applied periodically to the bias electrode.

[0079] In the plasma processing apparatus 1, the high-frequency power supply 61 is configured to synchronously change the power level of the high-frequency electrical power HF within each cycle CY of the electrical bias EB. In one embodiment, the high-frequency power supply 61 can supply pulses of the high-frequency electrical power HF to the high-frequency electrode ( ) during the same period within each cycle CY of the electrical bias EB. Figure 1 In the example, it is base 18) and outer ring OR.

[0080] exist Figure 2 The example shown in (a) and Figure 3 In the example shown in (a), a pulse of high-frequency power HF is supplied to the high-frequency electrode during the first period P1. Figure 1In the example, the base (18) and the outer ring OR are shown. During the first period P1, the thickness of the sheath (plasma sheath) on the substrate W is small, and the impedance on the substrate W is small. Therefore, during the first period P1, the high-frequency power HF coupled to the plasma through the substrate W is relatively more than the high-frequency power HF coupled to the plasma around the outer ring OR. As a result, in these examples, the plasma density in the region above the center of the substrate W is relatively higher than the plasma density in the region above the edge of the substrate W. Therefore, according to these examples, it is possible to correct the plasma density distribution, which is high in the region above the edge of the substrate W and low in the region above the center of the substrate W, to a radially uniform density distribution. Furthermore, in these examples, it is also possible to adjust the radial plasma density distribution in the space outside the region including the region above the edge ring ER.

[0081] exist Figure 2 The example shown in (b) and Figure 3 In the example shown in (b), a pulse of high-frequency power HF is supplied to the high-frequency electrode during the second period P2. Figure 1 In the example, this refers to the base 18 and the outer ring OR. During the second period P2, the thickness of the sheath (plasma sheath) on the substrate W is large, and the impedance on the substrate W is high. Therefore, during the second period P2, the high-frequency power HF coupled to the plasma around the outer ring OR is relatively more than the high-frequency power HF coupled to the plasma through the substrate W. As a result, in these examples, the plasma density in the region above the edge of the substrate W is higher. Therefore, in these examples, it is possible to correct the plasma density distribution, which is low in the region above the edge of the substrate W and high in the region above the center of the substrate W, to a radially uniform density distribution. Furthermore, in these examples, it is also possible to adjust the radial plasma density distribution in the space outside the region including the region above the edge ring ER.

[0082] In the plasma processing apparatus 1, the power level of the high-frequency electrical HF within each cycle CY is changed by controlling the high-frequency power supply 61 based on the control unit MC. In one embodiment of the plasma processing apparatus 1, the supply timing of the high-frequency electrical HF pulses can be set by controlling the high-frequency power supply 61 based on the control unit MC. Furthermore, the high-frequency electrodes ( Figure 1 In the example, the high-frequency power distribution ratio between the base plate 18 and the outer ring OR can be set by controlling the impedance of the impedance regulator 84 based on the control unit MC. Furthermore, the bias electrode ( Figure 1In the example, the distribution ratio of the electrical bias EB between the base 18 and the edge ring ER can be set by controlling the impedance of the impedance regulator 83 based on the control unit MC.

[0083] The control unit MC can determine the thickness of the edge ring ER based on measurements from one or more sensors or the usage time of the edge ring ER. Based on the determined edge ring ER thickness, the control unit MC adjusts the impedance of the impedance regulator 83 in a radially homogenized manner to adjust the height of the plasma-sheath interface. The control unit MC can pre-store the relationship between the edge ring ER thickness and the impedance of the impedance regulator 83 in its storage device in the form of a table or function. The control unit MC can use this relationship and determine the impedance of the impedance regulator 83 based on the edge ring ER thickness.

[0084] The control unit MC can set the impedance of the impedance regulator 84 in a manner that homogenizes the radial plasma density distribution based on the specific thickness of the edge ring ER or one or more measured values ​​obtained by one or more sensors. The one or more sensors may include sensors that measure the plasma density distribution in the internal space 10s. The one or more sensors may include sensors that measure the voltages of the substrate W, the edge ring ER, and the outer ring OR. The one or more sensors may include sensors that measure the currents flowing to the substrate W, the edge ring ER, and the outer ring OR, respectively. The one or more sensors may include sensors that measure the luminous intensity distribution in the internal space 10s. The control unit MC may also store in its storage device the relationship between the specific thickness of the edge ring ER or one or more measured values ​​obtained by one or more sensors and the impedance of the impedance regulator 84 in the form of a table or function. The control unit MC may also use this relationship and determine the impedance of the impedance regulator 84 based on the thickness of the edge ring ER or one or more measured values ​​obtained by one or more sensors.

[0085] According to the plasma processing device 1, the bias electrode is adjusted by the impedance regulator 83. Figure 1 In this example, the distribution ratio of the electrical bias EB between the base 18 and the edge ring ER is used. Therefore, the level of the negative bias in the edge ring ER is adjusted by the impedance regulator 83. Thus, the thickness of the sheath on the edge ring ER can be adjusted. Furthermore, in the plasma processing apparatus 1, the power level of the high-frequency power HF supplied to the outer ring OR in each cycle CY of the electrical bias EB is changed. Therefore, according to the plasma processing apparatus 1, the radial plasma density distribution can be adjusted in each cycle CY.

[0086] Furthermore, when a high-frequency power pulse (HF) is supplied to the high-frequency electrode and the outer ring OR during the first period P1, the plasma density on the substrate W and the plasma density around the outer ring OR can be increased. And when a high-frequency power pulse (HF) is supplied to the high-frequency electrode and the second electrode 82 during the second period P2, the plasma density around the outer ring OR can be relatively increased relative to the plasma density on the substrate W. Therefore, according to the plasma processing apparatus 1, the radial plasma density distribution can be adjusted within each cycle CY.

[0087] The plasma processing method using plasma processing apparatus 1 will now be described. The plasma processing method includes step (a1) and step (b1). In step (a1), in order to generate plasma from gas within chamber 10, high-frequency power HF is supplied from high-frequency power supply 61 to high-frequency electrodes (…). Figure 1 In the example, this is base 18. In step (b1), an electrical bias EB is applied from bias power supply 62 to the bias electrode ( Figure 1 In the example, this is base station 18). In process (a1), the high-frequency power supply 61 changes the power level of the high-frequency power HF synchronously with the electrical bias EB in each cycle CY.

[0088] In process (a1), the high-frequency power supply 61 can supply power to the high-frequency electrode (a1) during the same period of each cycle CY. Figure 1 The base 18 and the second electrode 82 are supplied with high-frequency power (HF) pulses. The same period can be either the first period P1 or the second period P2 within the period CY.

[0089] The following is for reference. Figure 4 . Figure 4 This is a schematic diagram illustrating a plasma processing apparatus according to another exemplary embodiment. The following describes... Figure 4 The differences between the plasma processing device 1B and the plasma processing device 1 will be explained.

[0090] The plasma processing apparatus 1B does not include an impedance regulator 84. In addition to the high-frequency power supply 61 (first high-frequency power supply) that generates high-frequency power HF (first high-frequency power), the plasma processing apparatus 1B also includes a high-frequency power supply 91 as a second high-frequency power supply. The high-frequency power supply 91 is configured to generate high-frequency power HF2 (second high-frequency power) supplied to the second electrode 82. The frequency of the high-frequency power generated by the high-frequency power supply 91 may be the same as or different from the frequency of the high-frequency power HF.

[0091] The high-frequency power supply 91 is connected to the outer ring OR via integrator 93 and electrical path 75. The high-frequency power supply 91 can be connected to the second electrode 82 via integrator 93 and electrical path 75. Integrator 93 has an integration circuit configured to integrate the impedance on the load side of the high-frequency power supply 91 with the output impedance of the high-frequency power supply 91.

[0092] In one embodiment, the electrical path 75 may include multiple branch lines connected to multiple locations on the outer ring OR (or the second electrode 82). The multiple locations are equidistant from the axis AX and are arranged at equal intervals circumferentially relative to the axis AX. Furthermore, the multiple branch lines of the electrical path 75 are arranged at equal intervals circumferentially relative to the axis AX. Also, the electrical lengths of the electrical path 75 relative to the multiple locations on the outer ring OR (or the second electrode 82) are approximately equal to each other. According to this embodiment, the outer ring OR can be uniformly powered via the electrical path 75.

[0093] The following, with Figure 4 Let's refer to each other. Figure 5 of (a), Figure 5 (b) Figure 6 (a) and Figure 6 (b) Figure 5 (a) and Figure 5 (b) are respectively Figure 4 The timing diagram of the first high-frequency power, the second high-frequency power, and the electrical bias used in an example of the plasma processing apparatus shown is illustrated. Figure 6 (a) and Figure 6 (b) are respectively Figure 4 The timing diagram of the first high-frequency power, the second high-frequency power, and the electrical bias used in another example of the plasma processing apparatus shown is illustrated. Figure 5 of (a), Figure 5 (b) Figure 6 (a) and Figure 6 (b) represents the power level of high-frequency power HF (first high-frequency power), the power level of high-frequency power HF2 (second high-frequency power), and the voltage level of electrical bias EB.

[0094] exist Figure 5 of (a), Figure 5 (b) Figure 6 (a) and Figure 6In (b), "H" for high-frequency power HF indicates a high power level. "L" for high-frequency power HF indicates a lower power level than indicated by "H". "ON" for high-frequency power HF indicates that high-frequency power HF is being supplied, and "OFF" for high-frequency power HF indicates that the supply of high-frequency power HF is stopped, i.e., the high-frequency power is HF0 (W). In these figures, "H" for high-frequency power HF2 indicates a high power level, and "L" for high-frequency power HF2 indicates that the power level of high-frequency power HF2 is lower than indicated by "H". "ON" for high-frequency power HF2 indicates that high-frequency power HF2 is being supplied, and "OFF" for high-frequency power HF2 indicates that the supply of high-frequency power HF2 is stopped, i.e., the high-frequency power HF2 is 0 (W). Furthermore, "ON" for electrical bias EB indicates that a voltage pulse (e.g., a negative DC voltage pulse) is applied to base 18. Furthermore, "OFF" for electrical bias EB indicates that the voltage pulse is stopped, i.e., the voltage of electrical bias EB is 0 (V).

[0095] Regarding the plasma processing apparatus 1, similarly to the electrical bias EB described above, in the plasma processing apparatus 1B, the first period P1 is the period during which the electrical bias EB has a voltage higher than the average voltage of the electrical bias EB within the period CY. The first period P1 is, for example, a period during which the electrical bias EB has a positive or zero voltage. The second period P2 is the period during which the electrical bias EB has a voltage lower than the aforementioned average voltage. The second period P2 is, for example, a period during which the electrical bias EB has a negative voltage. Figure 5 (a) and Figure 6 As shown in (a), the electrical bias EB can be a high-frequency bias power. Or, as... Figure 5 (b) and Figure 6 As shown in (b), the electrical bias EB may include pulses of voltage (e.g., pulses of negative DC voltage) applied periodically to the base 18.

[0096] In the plasma processing apparatus 1B, the high-frequency power supply 91 is configured to synchronously change the power level of the high-frequency power HF2 within each cycle CY of the electrical bias EB. In one embodiment, the high-frequency power supply 91 may be configured to supply pulses of the high-frequency power HF2 to the outer ring OR during the same period of each cycle CY.

[0097] exist Figure 5 The example shown in (a) and Figure 5 In the example shown in (b), a pulse of high-frequency power HF2 is supplied to the outer ring OR during the first period P1. In these examples, as in Figure 5 (a) and Figure 5 As shown by the solid line in (b), a pulse of high-frequency power HF can be supplied to the high-frequency electrode during the second period P2. Figure 4In the example, this is base 18 and edge ring ER. Or, in these examples, such as in Figure 5 (a) and Figure 5 As shown by the dashed line in (b), the continuous wave of high-frequency power (HF) can be supplied to the high-frequency electrode during both the first period P1 and the second period P2. Figure 4 In the example, it is base 18 and edge ring ER.

[0098] exist Figure 5 The example shown in (a) and Figure 5 In the example shown in (b), the pulse of high-frequency power HF2 supplied during the first period P1 increases the plasma density around the outer ring OR. Furthermore, a larger portion of the high-frequency power HF supplied during the second period P2 couples with the plasma around the outer ring OR. As a result, in these examples, the plasma density in the region above the edge of the substrate W is relatively higher than the plasma density in the region above the center of the substrate W. Therefore, according to these examples, it is possible to correct the plasma density distribution, which is low in the region above the edge of the substrate W and high in the region above the center of the substrate W, to a radially uniform density distribution. Furthermore, in these examples, it is also possible to adjust the radial plasma density distribution in the space outside the region including the region above the edge ring ER.

[0099] exist Figure 6 The example shown in (a) and Figure 6 In the example shown in (b), a pulse of high-frequency power HF2 is supplied to the outer ring OR during the first period P1. In these examples, a pulse of high-frequency power HF is supplied to the high-frequency electrode ( Figure 4 In the example, the base plate 18 and the edge ring ER are used. During the first period P1, the thickness of the sheath (plasma sheath) on the substrate W is small, and the impedance on the substrate W is small. Therefore, the high-frequency power HF coupled to the plasma through the center of the substrate W is relatively more. As a result, in these examples, the plasma density in the region above the center of the substrate W is higher. Therefore, in these examples, the plasma density distribution, which is high in the region above the edge of the substrate W and low in the region above the center of the substrate W, can be corrected to a radially uniform density distribution. Furthermore, in these examples, the radial plasma density distribution can be adjusted in the space outside the region including the region above the edge ring ER by the high-frequency power HF2 supplied during the first period P1.

[0100] In plasma processing apparatus 1B, the supply of high-frequency power HF within each cycle CY is controlled by the high-frequency power supply 61 based on the control unit MC. Furthermore, the change in the power level of high-frequency power HF2 within each cycle CY is controlled by the high-frequency power supply 91 based on the control unit MC. Also, in plasma processing apparatus B1, the high-frequency electrodes ( Figure 4 In the example, the distribution ratio of the electrical bias EB between the base 18 and the edge ring ER can be set by controlling the impedance of the impedance regulator 83 based on the control unit MC. Similarly, the control unit MC of the plasma processing apparatus 1 can determine the impedance of the impedance regulator 83 based on the thickness of the edge ring ER.

[0101] In the plasma processing apparatus 1B, the control unit MC can adjust the settings of the high-frequency power supply 61 and high-frequency power supply 91 in a manner that homogenizes the radial plasma density distribution, based on the specific thickness of the edge ring ER or one or more measured values ​​obtained by one or more sensors. That is, the control unit MC can adjust the supply timing and power level of high-frequency power HF2, and the supply timing and power level of high-frequency power HF3. One or more sensors may include sensors that measure the plasma density distribution in the internal space 10s. One or more sensors may include sensors that measure the voltages of the substrate W, the edge ring ER, and the outer ring OR. One or more sensors may include sensors that measure the currents flowing to the substrate W, the edge ring ER, and the outer ring OR, respectively. One or more sensors may include sensors that measure the luminous intensity distribution in the internal space 10s. The control unit MC may also store in advance the relationship between the specific thickness of the edge ring ER or one or more measured values ​​obtained by one or more sensors and the settings of the high-frequency power supply 61 and high-frequency power supply 91 in the storage device in the form of a table or function. The control unit MC can also use this relationship to determine the settings of the high-frequency power supply 61 and the high-frequency power supply 91 based on the thickness of the edge ring ER or one or more measured values ​​measured by one or more sensors.

[0102] In addition, Figure 5 of (a), Figure 5 (b) Figure 6 (a) and Figure 6 In the example shown in (b), the power level of the high-frequency power HF2 in the second period P2 can be set to the level indicated by "L", instead of 0. During the second period P2, there is a tendency for a relatively large decrease in plasma density around the outer ring OR. Therefore, by supplying high-frequency power HF2 to the outer ring OR during the second period P2, it is possible to control the variation in the radial plasma density distribution.

[0103] In the plasma processing apparatus 1B, the distribution ratio of the electrical bias EB between the high-frequency electrode and the edge ring ER is adjusted by the impedance regulator 83. Therefore, the level of the negative bias in the edge ring ER is adjusted. Thus, the thickness of the sheath layer on the edge ring ER can be adjusted. Furthermore, the power level of the high-frequency power HF2 supplied to the outer ring OR in each cycle CY is changed. Therefore, according to the plasma processing apparatus 1B, the radial plasma density distribution can be adjusted in each cycle CY. Furthermore, in the plasma processing apparatus 1B, the radial plasma density distribution is adjusted in each cycle CY based on the ratio of the high-frequency power HF2 supplied to the outer ring OR during the first period P1 when the sheath layer on the substrate W is thin to the high-frequency power HF supplied to the high-frequency electrode.

[0104] The plasma processing method using plasma processing apparatus 1B will now be described. The plasma processing method includes steps (a2), (b2), and (c2). In step (a2), in order to generate plasma from gas within chamber 10, high-frequency power HF is supplied from high-frequency power supply 61 to high-frequency electrodes (…). Figure 4 In the example, this is base 18. In step (b2), an electrical bias EB is applied from bias power supply 62 to the bias electrode ( Figure 4 In the example, this is base station 18). In step (c2), high-frequency power HF2 is supplied from high-frequency power supply 91 to the outer ring OR. In step (c2), high-frequency power supply 91 changes the power level of high-frequency power HF2 synchronously with electrical bias EB in each cycle CY.

[0105] In process (c2), the high-frequency power supply 61 can supply pulses of high-frequency power HF2 to the second electrode 82 during the same period within each cycle CY. The same period can be the first period P1 within the cycle CY.

[0106] The following is for reference. Figure 7 . Figure 7 This is a schematic diagram illustrating a plasma processing apparatus according to yet another exemplary embodiment. The following describes... Figure 7 The differences between plasma processing device 1C and plasma processing device 1B shown will be explained.

[0107] The plasma processing apparatus 1C does not include an impedance regulator 83. In the plasma processing apparatus 1C, a bias power supply 92 is connected to the edge ring ER (or the first electrode 81) via an integrator 94 and an electrical path 72. The bias power supply 92 is the same power supply as the bias power supply 62. The integrator 94 includes an integration circuit for integrating the impedance on the load side of the bias power supply 92 with the output impedance of the bias power supply 92.

[0108] In the plasma processing apparatus 1C, the control unit MC can determine the thickness of the edge ring ER based on measurements from one or more sensors or the usage time of the edge ring ER. The control unit MC can set the level of the electrical bias generated by the bias power supply 92 in a radially uniform manner based on the determined edge ring ER thickness, thereby homogenizing the position of the plasma-sheath interface in the height direction. The control unit MC can also pre-store the relationship between the edge ring ER thickness and the electrical bias generated by the bias power supply 92 in its storage device in the form of a table or function. The control unit MC can also use this relationship to determine the level of the electrical bias generated by the bias power supply 92 based on the edge ring ER thickness.

[0109] In addition, in the plasma processing apparatus 1C, other high-frequency power sources that generate high-frequency power can be electrically connected to the edge ring ER (or the first electrode 81) via an integrator.

[0110] The following is for reference. Figure 8 . Figure 8 This is a schematic diagram illustrating a plasma processing apparatus according to yet another exemplary embodiment. The following describes... Figure 8 The differences between the plasma processing apparatus 1D and the plasma processing apparatus 1C will be explained. In the plasma processing apparatus 1D, a bias electrode 21 is disposed in the electrostatic chuck 20. The bias electrode 21 may also serve as a chuck electrode, or it may be a different electrode from the chuck electrode. In the plasma processing apparatus 1D, the bias power supply 62 is connected to the bias electrode 21 via an electrical path different from the electrical path 71.

[0111] The above descriptions have illustrated various exemplary embodiments, but the embodiments are not limited to these exemplary embodiments. Various additions, omissions, substitutions, and modifications can be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0112] For example, in another embodiment, the high-frequency power supply 61 may be connected to the upper electrode 30 via the integrator 63 instead of to the base plate 18. In this case, the upper electrode 30 is used as a high-frequency electrode.

[0113] In another embodiment, when the high-frequency power supply 61 is connected to the base station 18 via the electrical path 71, the impedance regulator 83 can be connected between the electrical path 71 and the edge ring ER (or the first electrode 81).

[0114] In another embodiment, the outer ring OR can be positioned vertically above the edge ring ER. In yet another embodiment, the outer ring OR can be configured to surround the upper electrode 30. In this case, the outer ring OR can be configured within the component 32.

[0115] In another embodiment, the impedance regulator 84 may be connected between the base 18 and the outer ring OR (or the second electrode 82).

[0116] In another embodiment, an additional bias power source may be connected to the outer ring OR (or the second electrode 82) via electrical path 75. The additional bias power source may generate high-frequency bias power supplied to the outer ring OR, or it may periodically generate pulsed voltages or voltages with arbitrary waveforms applied to the outer ring OR.

[0117] As can be understood from the above description, various embodiments of the present invention have been described in this specification for illustrative purposes, and various modifications can be made without departing from the scope and spirit of the invention. Therefore, the embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are indicated by the scope of the appended claims.

Claims

1. A plasma processing apparatus, comprising: chamber; A substrate support having bias electrodes; A high-frequency power supply generates high-frequency electricity to be supplied to high-frequency electrodes in order to generate plasma above a substrate supported by the substrate support within the cavity; and A bias power supply is connected to the bias electrode via an electrical path. An edge ring mounted on the substrate support is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or to other bias power supplies. The outer ring, extending radially outward relative to the edge ring, is electrically connected to the high-frequency power source in a manner that receives a portion of the high-frequency power. The high-frequency power supply is configured to change the power level of the high-frequency power supply synchronously with the electrical bias during each cycle of the electrical bias output from the bias power supply to the bias electrode. The plasma processing device also includes: The first electrode is electrically coupled to the edge ring; and The second electrode is electrically coupled to the outer ring. The impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives a portion of the high-frequency power or other high-frequency power from other high-frequency power sources via the second electrode.

2. The plasma processing apparatus according to claim 1, wherein, The high-frequency power supply is configured to supply pulses of high-frequency power to the high-frequency electrode and the outer ring during the same period of each cycle of the electrical bias.

3. The plasma processing apparatus according to claim 2, wherein, The same period is either a first period in which the electrical bias has a voltage greater than the average voltage of the electrical bias within its cycle, or a second period in which the electrical bias has a voltage lower than the average voltage within its cycle.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein, The substrate support has a base and an electrostatic chuck disposed on the base. The base provides a lower electrode that serves as the bias electrode. The lower electrode is the high-frequency electrode. The high-frequency power supply is electrically connected to the lower electrode via the electrical path.

5. The plasma processing apparatus according to claim 4, further comprising: An impedance regulator with variable impedance is provided between the electrical path and the outer ring or between the lower electrode and the outer ring.

6. The plasma processing apparatus according to claim 5, further comprising: A filter is connected between the impedance regulator and the outer ring, the impedance regulator providing variable impedance between the electrical path and the outer ring or between the lower electrode and the outer ring. The filter has frequency characteristics that allow the high-frequency power to selectively pass through the electrical bias supplied from the bias power supply to the lower electrode.

7. The plasma processing apparatus according to any one of claims 1 to 3, wherein, The substrate support has a base and an electrostatic chuck disposed on the base. The bias electrode is disposed in the electrostatic chuck. The base provides a lower electrode that serves as the high-frequency electrode. The high-frequency power supply is electrically connected to the lower electrode.

8. The plasma processing apparatus according to claim 7, further comprising: An impedance regulator provides variable impedance between the electrical path connecting the high-frequency power supply to the lower electrode and the outer ring, or between the lower electrode and the outer ring.

9. A plasma processing apparatus, comprising: chamber; A substrate support having bias electrodes; The first high-frequency power supply generates a first high-frequency power supplied to the high-frequency electrodes in order to generate plasma above the substrate supported by the substrate support within the cavity; and A bias power supply is connected to the bias electrode via an electrical path. The second high-frequency power source is configured to generate a second high-frequency power supply to the outer ring, and the outer ring extends radially and outward relative to the edge ring mounted on the substrate support. The edge ring is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or to other bias power supplies. The second high-frequency power supply is configured to change its power level synchronously with the electrical bias during each cycle of the electrical bias output from the bias power supply to the bias electrode. The plasma processing device also includes: The first electrode is electrically coupled to the edge ring; and The second electrode is electrically coupled to the outer ring. The impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives the second high-frequency power via the second electrode.

10. The plasma processing apparatus according to claim 9, wherein, The substrate support has a base and an electrostatic chuck disposed on the base. The base provides a lower electrode that serves as the bias electrode. The lower electrode is the high-frequency electrode. The first high-frequency power supply is electrically connected to the lower electrode via the electrical path.

11. The plasma processing apparatus according to claim 9, wherein, The substrate support has a base and an electrostatic chuck disposed on the base. The bias electrode is disposed in the electrostatic chuck. The base provides a lower electrode that serves as the high-frequency electrode. The first high-frequency power supply is electrically connected to the lower electrode.

12. The plasma processing apparatus according to any one of claims 9 to 11, wherein, The second high-frequency power supply is configured to supply pulses of the second high-frequency power to the outer ring during the same period of each cycle of the electrical bias.

13. The plasma processing apparatus according to claim 12, wherein, Each cycle of the electrical bias includes a first period in which the electrical bias has a voltage greater than the average voltage of the electrical bias within the cycle, or a second period in which the electrical bias has a voltage lower than the average voltage within the cycle. The same period refers to the first period.

14. The plasma processing apparatus according to claim 13, wherein, The first high-frequency power source supplies a continuous wave of the first high-frequency power during both the first and second periods, or a pulse of the first high-frequency power during the second period.

15. The plasma processing apparatus according to claim 13, wherein, The first high-frequency power source supplies pulses of the first high-frequency power during the first period.

16. The plasma processing apparatus according to any one of claims 9 to 11, wherein, The outer ring extends in a manner that surrounds the edge ring.

17. The plasma processing apparatus according to any one of claims 1 to 3 and claims 9 to 11, wherein, The bias power supply is configured to supply high-frequency bias power to the bias electrode, or to periodically apply a voltage with a pulsed pattern or an arbitrary waveform to the bias electrode.

18. A plasma processing method, comprising: (a1) A process of supplying high-frequency power from a high-frequency power source to high-frequency electrodes in order to generate plasma above a substrate supported by a substrate support within the chamber of a plasma processing apparatus; and (b1) The process of applying an electrical bias from a bias power supply to the bias electrode of the substrate support. The plasma processing device includes: The chamber: The substrate support; The high-frequency power supply; and The bias power supply is connected to the bias electrode via an electrical path. An edge ring mounted on the substrate support is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or to other bias power supplies. Electrically connected to the high-frequency power source in a manner that the outer ring extends radially and outward relative to the edge ring to receive a portion of the high-frequency power. In (a1), the high-frequency power supply synchronously changes the power level of the high-frequency power supply with respect to the electrical bias during each cycle of the electrical bias output from the bias power supply to the bias electrode. The plasma processing device also includes: The first electrode is electrically coupled to the edge ring; and The second electrode is electrically coupled to the outer ring. The impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives a portion of the high-frequency power or other high-frequency power from other high-frequency power sources via the second electrode.

19. The plasma processing method according to claim 18, wherein, In (a1), the high-frequency power supply supplies pulses of the high-frequency power to the high-frequency electrode and the outer ring during the same period of each cycle of the electrical bias.

20. The plasma processing method according to claim 19, wherein, The same period is either a first period in which the electrical bias has a voltage greater than the average voltage of the electrical bias within its cycle, or a second period in which the electrical bias has a voltage lower than the average voltage within its cycle.

21. A plasma processing method, comprising: (a2) A process of supplying a first high-frequency power from a first high-frequency power source to a high-frequency electrode in order to generate plasma above a substrate supported by a substrate support in the chamber of a plasma processing apparatus. (b2) The process of applying electrical bias from a bias power supply to the bias electrode of the substrate support; and (c2) The process of supplying second high-frequency power from the second high-frequency power source to the outer ring. The plasma processing device includes: The chamber: The substrate support; The first high-frequency power supply; The bias power supply is connected to the bias electrode via an electrical path; and The second high-frequency power supply, An edge ring mounted on the substrate support is electrically connected to the bias power supply via an impedance regulator that provides variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or to other bias power supplies. The outer ring extends radially and outward relative to the edge ring. In (c2), the second high-frequency power supply changes its power level synchronously with the electrical bias during each cycle of the electrical bias. The plasma processing device also includes: The first electrode is electrically coupled to the edge ring; and The second electrode is electrically coupled to the outer ring. The impedance regulator provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives the second high-frequency power via the second electrode.

22. The plasma processing method according to claim 21, wherein, In (c2), the second high-frequency power supply supplies pulses of the second high-frequency power to the outer ring during the same period of each cycle of the electrical bias.

23. The plasma processing method according to claim 22, wherein, Each cycle of the electrical bias includes a first period in which the electrical bias has a voltage greater than the average voltage of the electrical bias within the cycle, or a second period in which the electrical bias has a voltage lower than the average voltage within the cycle. The same period refers to the first period.

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