Plasma processing apparatus and plasma processing method

Abstract

The disclosed plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, a bias power supply, and a control unit. The bias power supply is configured to periodically apply a pulsed negative DC voltage to the substrate support. The control unit is configured to control the high-frequency power supply. In order to reduce the power level of the reflected wave from the load of the high-frequency power supply, the control unit controls the high-frequency power supply to supply high-frequency power with varying frequency during the period of applying the pulsed negative DC voltage from the bias power supply to the substrate support.

Description

Technical Field

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

[0002] In plasma processing of substrates, a plasma processing apparatus is used. Patent Document 1 (Japanese Patent Application Publication No. 10-64915) discloses a plasma processing apparatus. The plasma processing apparatus disclosed in Patent Document 1 includes a chamber, electrodes, a high-frequency power supply, and a high-frequency bias power supply. Electrodes are disposed within the chamber. The substrate is placed on the electrodes. The high-frequency power supply supplies pulses of high-frequency power to generate a high-frequency electric field within the chamber. The high-frequency bias power supply supplies pulses of high-frequency bias power to the electrodes. Summary of the Invention

[0003] This invention provides a technique for reducing the power level of reflected waves from a load originating from a high-frequency power supply.

[0004] 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, a bias power supply, and a control unit. The substrate support has a base and an electrostatic chuck. The electrostatic chuck is disposed on the base. The substrate support is configured to support a substrate placed thereon within the chamber. The high-frequency power supply is configured to generate high-frequency power supplied for generating plasma from gas within the chamber. The bias power supply is electrically connected to the substrate support and is configured to periodically apply a pulsed negative DC voltage to the substrate support. The control unit is configured to control the high-frequency power supply. To reduce the power level of reflected waves from the load of the high-frequency power supply, the control unit controls the high-frequency power supply to supply high-frequency power with varying frequency during the period of applying the pulsed negative DC voltage from the bias power supply to the substrate support.

[0005] According to one exemplary implementation, it is possible to reduce the power level of reflected waves from a load originating from a high-frequency power source. Attached Figure Description

[0006] Figure 1 This is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment.

[0007] Figure 2 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0008] Figure 3 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0009] Figure 4This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0010] Figure 5 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0011] Figure 6 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0012] Figure 7 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0013] Figure 8 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0014] Figure 9 This is a timing diagram of a pulsed negative DC voltage, the power of a high-frequency power source, and the frequency of the high-frequency power source.

[0015] Figure 10 This is a flowchart illustrating a plasma processing method according to an exemplary embodiment. Detailed Implementation

[0016] The following describes various exemplary embodiments.

[0017] 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, a bias power supply, and a control unit. The substrate support has a base and an electrostatic chuck. The electrostatic chuck is disposed on the base. The substrate support is configured to support a substrate placed thereon within the chamber. The high-frequency power supply is configured to generate high-frequency power supplied for generating plasma from gas within the chamber. The bias power supply is electrically connected to the substrate support and is configured to periodically apply a pulsed negative DC voltage to the substrate support. The control unit is configured to control the high-frequency power supply. To reduce the power level of reflected waves from the load of the high-frequency power supply, the control unit controls the high-frequency power supply to supply high-frequency power with varying frequency during the period of applying the pulsed negative DC voltage from the bias power supply to the substrate support.

[0018] Reflection from a load due to a high-frequency power supply is caused by the difference between the output impedance of the high-frequency power supply and the load impedance. This difference can be reduced by varying the frequency of the high-frequency power supply. Therefore, according to the above embodiment, the power level of the reflected wave from the load due to the high-frequency power supply can be reduced. Furthermore, the load impedance changes during the application period of the pulsed negative DC voltage, i.e., the pulse period. Typically, the frequency of the high-frequency power supply can be changed much faster than the impedance change rate based on the matching converter. Therefore, according to the above embodiment, the frequency of the high-frequency power supply can be changed rapidly according to the change in load impedance to reduce the power level of the reflected wave within the period.

[0019] In one exemplary embodiment, the control unit may control the high-frequency power supply to supply high-frequency power for at least a portion of a first period within the cycle. The control unit may also control the high-frequency power supply to set the power level of the high-frequency power during a second period within the cycle to a power level reduced from the power level of the high-frequency power during the first period.

[0020] In one exemplary embodiment, the first period may also be the period during which a pulsed negative DC voltage is applied to the substrate support. The second period may also be the period during which a pulsed negative DC voltage is not applied to the substrate support.

[0021] In one exemplary embodiment, the first period may also be a period during which a pulsed negative DC voltage is not applied to the substrate support. The second period may also be a period during which a pulsed negative DC voltage is applied to the substrate support.

[0022] In one exemplary embodiment, the control unit can control a high-frequency power supply to change its frequency according to the phase within the period in order to reduce the power level of the reflected wave during the period. The control unit can use a pre-determined relationship between the phase within the period and the frequency of the high-frequency power supply for reducing the power level of the reflected wave during the period to control the high-frequency power supply to change its frequency according to the phase within the period.

[0023] In another exemplary embodiment, a plasma processing method is provided. The plasma processing apparatus used in the plasma processing method includes a chamber, a substrate support, a high-frequency power supply, and a bias power supply. The substrate support has a base and an electrostatic chuck. The electrostatic chuck is disposed on the base. The substrate support is configured to support a substrate placed thereon within the chamber. The high-frequency power supply is configured to generate high-frequency power supplied for generating plasma from gas within the chamber. The bias power supply is electrically connected to the substrate support. The plasma processing method is performed to perform plasma processing on the substrate while it is placed on the electrostatic chuck. The plasma processing method includes a step of periodically applying a pulsed negative DC voltage from the bias power supply to the substrate support. The plasma processing method includes a step of supplying high-frequency power with a varying frequency to the substrate support during the period of applying the pulsed negative DC voltage from the bias power supply to the substrate support in order to reduce the power level of reflected waves from the load of the high-frequency power supply.

[0024] In one exemplary embodiment, high-frequency power can be supplied for at least a portion of the first period within the cycle. The power level of the high-frequency power during the second period within the cycle can be set to a power level reduced from the power level of the high-frequency power during the first period.

[0025] In one exemplary embodiment, the first period may also be the period during which a pulsed negative DC voltage is applied to the substrate support. The second period may also be the period during which a pulsed negative DC voltage is not applied to the substrate support.

[0026] In one exemplary embodiment, the first period may also be a period during which a pulsed negative DC voltage is not applied to the substrate support. The second period may also be a period during which a pulsed negative DC voltage is applied to the substrate support.

[0027] In one exemplary embodiment, in order to reduce the power level of the reflected wave within a period, the frequency of the high-frequency power can be varied according to the phase within the period. The frequency of the high-frequency power can be varied according to the phase within the period using a pre-determined relationship between the phase within the period and the frequency of the high-frequency power for reducing the power level of the reflected wave within the period.

[0028] 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.

[0029] Figure 1 This is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment. Figure 1The 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 vertically.

[0030] In one embodiment, the chamber 10 includes 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 yttrium oxide.

[0031] A channel 12p is formed on the side wall of the chamber body 12. When the substrate W is transported between the internal space 10s and the outside of the chamber 10, it passes through the channel 12p. A gate valve 12g is provided along the side wall of the chamber body 12 for opening and closing the channel 12p.

[0032] The plasma processing apparatus 1 also includes a substrate support 16. The substrate support 16 is configured to support a substrate W placed thereon within the chamber 10. The substrate W has a generally disc-shaped form. The substrate support 16 is supported by a support portion 17. The support portion 17 extends upward from the bottom of the chamber body 12. The support portion 17 has a generally cylindrical shape. The support portion 17 is formed of an insulating material such as quartz or alumina.

[0033] The substrate support 16 has a base 18 and an electrostatic chuck 20. The base 18 and the electrostatic chuck 20 are disposed in the chamber 10. The base 18 is formed of a conductive material such as aluminum and has a generally disc-shaped form.

[0034] A flow path 18f is formed within the base 18. Flow path 18f is a flow path for the heat exchange medium. A liquid refrigerant or a refrigerant that cools the base 18 by vaporization (e.g., chlorofluorocarbon) is used as the heat exchange medium. A supply device (e.g., a cooling unit) for the heat exchange medium is connected to the flow path 18f. This supply device is located outside the chamber 10. The heat exchange medium is supplied from the supply device to the flow path 18f via pipe 23a. The heat exchange medium supplied to the flow path 18f returns to the supply device via pipe 23b.

[0035] An electrostatic chuck 20 is disposed on the base 18. When 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.

[0036] The electrostatic chuck 20 has a main body and chuck electrodes. The main body of the electrostatic chuck 20 is formed of a dielectric such as aluminum oxide or aluminum nitride. The main body of the electrostatic chuck 20 has a generally disc-shaped form. The central axis of the electrostatic chuck 20 is approximately aligned with axis AX. The chuck electrodes are disposed within the main body. The chuck electrodes have a film shape. A DC power supply is connected to the chuck electrodes 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.

[0037] 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 approximately aligned with axis AX. When processed within the chamber 10, the substrate W is placed on the upper surface of the substrate placement area.

[0038] 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 about 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 has a ring shape. The edge ring ER is mounted on the edge ring mounting region with its central axis aligned with axis AX. The substrate W is disposed within the region surrounded by the edge ring ER. That is, the edge ring ER is configured to surround the edge of the substrate W. The edge ring ER may be conductive. The edge ring ER may be formed, for example, of silicon or silicon carbide. The edge ring ER may be formed of a dielectric such as quartz.

[0039] The plasma processing apparatus 1 may also include a gas supply line 25. The gas supply line 25 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 surface (lower surface) of the substrate W.

[0040] The plasma processing apparatus 1 may also include an insulating region 27. The insulating region 27 is disposed on the support portion 17. The insulating region 27 is radially disposed on the outer side of the base 18 relative to the axis AX. The insulating region 27 extends circumferentially along the outer peripheral surface of the base 18. The insulating region 27 is formed of an insulator such as quartz. An edge ring ER is placed on the insulating region 27 and the edge ring placement area.

[0041] 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.

[0042] The upper electrode 30 includes a top plate 34 and a support 36. The lower surface of the top plate 34 divides an internal space 10s. A plurality of vent holes 34a are formed on the top plate 34. The plurality of vent holes 34a penetrate the top plate 34 along the thickness direction (vertical direction). The top plate 34 is not limited, for example, it is formed of silicon. 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 film formed by anodizing or a ceramic film such as a film formed of yttrium oxide.

[0043] The support body 36 detachably supports the top plate 34. The support body 36 is formed of a conductive material, such as aluminum. A gas diffusion chamber 36a is provided inside the support body 36. Multiple gas holes 36b extend downward from the gas diffusion chamber 36a. The multiple gas holes 36b communicate with multiple exhaust holes 34a. A gas inlet port 36c is formed in the support body 36. 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.

[0044] 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., on / off valves). The flow controller group 42 includes multiple flow controllers. The multiple flow controllers in the flow controller group 42 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, respectively. The plasma processing apparatus 1 can supply gas from one or more gas sources selected from the multiple gas sources of the gas source group 40 to the internal space for 10 seconds at individually regulated flow rates.

[0045] A baffle 48 is provided between the substrate support 16 or support portion 17 and the side wall of the chamber body 12. The baffle 48 can be constructed, for example, by coating an aluminum component with a ceramic such as yttrium oxide. Multiple through holes are formed in the baffle 48. Below the baffle 48, an exhaust pipe 52 is connected to the bottom of the chamber body 12. An exhaust device 50 is connected to the 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 10 seconds.

[0046] The plasma processing apparatus 1 also includes a high-frequency power supply 61. The high-frequency power supply 61 is a power source that generates high-frequency power RF. The high-frequency power RF is used to generate plasma from gas within the chamber 10. The frequency of the high-frequency power RF can be in the range of 27 to 100 MHz. The high-frequency power supply 61 supplies the high-frequency power RF to the substrate support 16 (in one example, the base 18). In one embodiment, the high-frequency power supply 61 is connected to the base 18 via a matching circuit 63, with the base 18 functioning as a lower electrode. The matching circuit 63 is configured to match the output impedance of the high-frequency power supply 61 with the impedance of the load side (e.g., the base 18 side), i.e., the load impedance. The high-frequency power supply 61 can also be electrically connected to the base 18 via a power sensor 65. The power sensor 65 can include a directional coupler and a reflected wave power detector. The directional coupler is configured to apply at least a portion of the reflected wave from the load of the high-frequency power supply 61 to the reflected wave power detector. The reflected wave power detector is configured to detect the power level of the reflected wave received from the directional coupler. Alternatively, the high-frequency power supply 61 may not be electrically connected to the base 18, but may be connected to the upper electrode 30 via the matching circuit 63.

[0047] The plasma processing apparatus 1 also includes a bias power supply 62. The bias power supply 62 is electrically connected to a substrate support 16 (in one example, a base 18). In one embodiment, the bias power supply 62 is electrically connected to the base 18 via a low-pass filter 64. The bias power supply 62 is configured to operate at a frequency of P... P That is, a pulsed negative DC voltage PV is periodically applied to the base 18. The period P is defined. P The frequency is lower than that of high-frequency power RF. Limited period P P The frequency is, for example, above 50kHz and below 27MHz. Period P P This includes a first period P1 and a second period P2. In one embodiment, the first period P1 may also be the period during which a pulsed negative DC voltage PV is applied to the base 18, and the second period P2 may also be the period during which the pulsed negative DC voltage PV is not applied to the base 18. In another embodiment, the first period P1 may also be the period during which the pulsed negative DC voltage PV is not applied to the base 18, and the second period P2 may also be the period during which the pulsed negative DC voltage PV is applied to the base 18.

[0048] In the plasma processing apparatus 1, gas is supplied to the internal space for 10 seconds. Then, by supplying high-frequency power RF, the gas in the internal space is excited for 10 seconds. As a result, plasma is generated in the internal space for 10 seconds. The substrate W, supported by the substrate support 16, is treated by chemical species such as ions and free radicals from the plasma. For example, the substrate is etched by chemical species from the plasma. In the plasma processing apparatus 1, a pulsed negative polarity DC voltage PV is applied to the base 18, and ions from the plasma are accelerated toward the substrate W.

[0049] The plasma processing apparatus 1 also includes 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. The control unit MC executes control programs stored in the storage device and controls each part of the plasma processing apparatus 1 according to process data stored in the storage device. Through the control of the control unit MC, the process specified by the process data is executed in the plasma processing apparatus 1. The plasma processing method described later can be executed in the plasma processing apparatus 1 through the control of each part of the plasma processing apparatus 1 based on the control unit MC.

[0050] In one embodiment, the control unit MC can control the high-frequency power supply 61 to make the period P P High-frequency power RF is supplied during at least a portion of the first period P1 within the plasma processing apparatus 1. In the plasma processing apparatus 1, the high-frequency power RF is supplied to the base 18. Alternatively, the high-frequency power RF may also be supplied to the upper electrode 30. The control unit MC may also control the period P... P The power level of the high-frequency power RF in the second part of the period P2 is set to a power level that is reduced from the power level of the high-frequency power RF in the first part of the period P1. That is, the control unit MC can also control the high-frequency power supply 61 to supply more than one pulse of the high-frequency power RF in the first part of the period P1.

[0051] During the second part, the power level of the high-frequency power RF in P2 can also be 0 [W]. That is, the control unit MC can also control the high-frequency power supply 61 to stop the supply of high-frequency power RF to P2 during the second part. Alternatively, the power level of the high-frequency power RF in P2 during the second part can also be greater than 0 [W].

[0052] The control unit MC is configured to provide a synchronization pulse, a delay duration, and a supply duration to the high-frequency power supply 61. The synchronization pulse is synchronized with a pulse-shaped negative DC voltage PV. The delay duration is a period P determined based on the synchronization pulse. P The delay duration at the start time. The supply duration is the length of the high-frequency power RF supply time. The high-frequency power supply 61 is in the period P.P The start time is delayed only by the delay duration until the supply duration, during which one or more pulses of high-frequency power RF are supplied. As a result, during the first part of the period P1, high-frequency power RF is supplied to the base 18. Alternatively, the delay duration can be zero.

[0053] In one embodiment, the plasma processing apparatus 1 may further include a voltage sensor 78. The voltage sensor 78 is configured to directly or indirectly measure the potential of the substrate W. Figure 1 In the example shown, voltage sensor 78 is configured to measure the potential of base 18. Specifically, voltage sensor 78 measures the potential of the power supply circuit connected between base 18 and bias power supply 62.

[0054] The control unit MC can also measure the potential ratio of the substrate W to the period P measured by the voltage sensor 78. P The average potential V of the substrate W in AVE The period of high or low voltage is defined as the first period, P1. The control unit MC can also use the average potential ratio V of the substrate W measured by the voltage sensor 78. AVE The period of low or high voltage is defined as period P2 in part 2. The average potential V of the substrate W. AVE This can be a preset value. The control unit MC can also control the high-frequency power supply 61 to supply high-frequency power RF as described above during the determined first period P1. Furthermore, the control unit MC can also control the high-frequency power supply 61 to set the power level of the high-frequency power RF as described above during the determined second period P2. Additionally, the plasma processing apparatus 1 can replace the voltage sensor 78 and be equipped with the ability to acquire the power level during period P. P Other sensors (e.g., current sensors) that can be used to determine the measured values ​​in the determination of the first period P1 and the second period P2.

[0055] In order to reduce the power level of the reflected wave from the load of the high-frequency power supply 61, the control unit MC controls the high-frequency power supply 61 to reduce the power level of the reflected wave during period P. P The internal high-frequency power RF supplies varying frequency power. This is used to reduce the periodicity P. P The period P of the power level of the reflected wave within P The relationship between the phase within the circuit and the frequency of the high-frequency power RF can be predetermined in the plasma processing apparatus 1 before or during the plasma processing of the substrate W. This relationship is stored in the storage device of the control unit MC as data in the form of a function or table. The control unit MC uses this relationship to control the high-frequency power supply 61. This relationship is determined by changing the cycle P. P While detecting the frequency of the high-frequency power RF in each phase, a power sensor 65 is used to detect the power level of the reflected wave to determine whether to suppress or minimize the period P.P The power level of the reflected wave in each phase is obtained from the frequency of the high-frequency power RF.

[0056] The reflection from the load of the high-frequency power supply 61 is caused by the difference between the output impedance of the high-frequency power supply 61 and the load impedance. The difference between the output impedance of the high-frequency power supply 61 and the load impedance can be reduced by varying the frequency of the high-frequency power RF. Therefore, according to the plasma processing apparatus 1, the power level of the reflected wave from the load of the high-frequency power supply 61 can be reduced. Furthermore, during the application period P of the pulsed negative polarity DC voltage PV... P Within the load impedance, the frequency of the high-frequency power supply changes much faster than the rate of change based on the impedance of the matching device. Therefore, according to the plasma processing apparatus 1, the frequency of the high-frequency power RF can be changed rapidly according to the change in load impedance, thereby reducing the power level of the reflected wave within the period PP.

[0057] Furthermore, during the period when a negatively polarized pulsed DC voltage PV is applied to the base 18, the potential difference between the plasma and the base 18 (or the substrate W) relatively increases. Therefore, during this period, secondary electrons generated by collisions between ions and the substrate W are accelerated by the larger potential difference between the plasma and the base 18 and the sheath applied to the substrate W, thus gaining greater energy. Consequently, during the period when the negatively polarized pulsed DC voltage PV is applied to the base 18, the energy of the secondary electrons is relatively high, and the electron temperature and the degree of gas dissociation in the plasma increase. On the other hand, during the period when the negatively polarized pulsed DC voltage PV is not applied to the base 18, the potential difference between the plasma and the base 18 (or the substrate W) relatively decreases. Therefore, during this period, the potential difference for accelerating secondary electrons is small, resulting in relatively low energy of the secondary electrons, and a lower electron temperature and a lower degree of gas dissociation in the plasma. Therefore, according to the plasma processing device 1, the electron temperature in the plasma and the degree of gas dissociation in the plasma can be controlled.

[0058] The following is for reference. Figures 2-9 . Figures 2-9 These are timing diagrams of a pulsed negative DC voltage, the power of the high-frequency power, and the frequency of the high-frequency power, respectively, in one example. Figures 2-9 In each of these terms, "VO", "RF power", and "RF frequency" represent the output voltage of the bias power supply 62, the power level of the high-frequency power RF, and the frequency of the high-frequency power RF, respectively.

[0059] exist Figure 2 In the example shown, during the first period, P1 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 2 In the example shown, during the second period, P2 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 2 In the example shown, the control unit MC controls the high-frequency power supply 61 to make it so that during period P P During the repetition period, high-frequency power (RF) is continuously supplied to generate plasma. Figure 2 In the example shown, during the transition period of the pulsed negative DC voltage PV from 0 [V] to the negative peak voltage (hereinafter referred to as the "first transition period"), the frequency of the high-frequency power RF changes in an increasing manner. Figure 2 In the example shown, during the transition period of the pulsed negative polarity DC voltage PV from its negative peak voltage to 0 [V] (hereinafter referred to as the "second transition period"), the frequency of the high-frequency power RF changes in a decreasing manner. Figure 2 In the example shown, the frequency of the high-frequency power RF in P1 during Part 1 is set to a higher frequency than the frequency of the high-frequency power RF in P2 during Part 2.

[0060] Figure 3 This is a timing diagram of another example involving a pulsed negative DC voltage, high-frequency power, and the frequency of the high-frequency power. Figure 3 In the timing diagram shown, even during the second part, P2, the frequency of the high-frequency power RF changes, which is consistent with... Figure 2 The timing diagrams shown are different. For example... Figure 3 As shown in the example, the frequency of the high-frequency power RF can be changed more than once during at least one of the first period P1 and the second period P2. That is, the frequency of the high-frequency power RF can be varied during at least one of the first period P1 and the second period P2.

[0061] exist Figure 4 In the example shown, during the first period, P1 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 4 In the example shown, during the second period, P2 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 4 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during the first part and to stop supplying high-frequency power RF to P2 during the second part. That is, in Figure 4 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply pulses of high-frequency power RF to P1 during Part 1. Figure 4 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 4In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner.

[0062] exist Figure 5 In the example shown, during the first period, P1 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 5 In the example shown, during the second period, P2 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 5 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during Part 1. Figure 5 In the example shown, the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second period P2 to a power level greater than 0 [W] and reduced from the power level of the high-frequency power RF in the first period P1. Figure 5 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 5 In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner. Figure 5 In the example shown, the frequency of the high-frequency power RF in P1 during Part 1 is higher than the frequency of the high-frequency power RF in P2 during Part 2.

[0063] exist Figure 6 In the example shown, during the first period, P1 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 6 In the example shown, during the second period, P2 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 6 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during Part 1. Figure 6 In the example shown, the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second period P2 to a power level reduced from the power level of the high-frequency power RF in the first period P1. Furthermore, in Figure 6 In the example shown, the control unit MC controls the high-frequency power supply 61 to change the power level of the high-frequency power RF during the second part period P2. Thus, the control unit MC can also control the high-frequency power supply 61 to change the power level of the high-frequency power RF more than once during at least one of the first part period P1 and the second part period P2.

[0064] exist Figure 6 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 6In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner. Figure 6 In the example shown, the frequency of the high-frequency power RF in P1 during Part 1 is higher than the frequency of the high-frequency power RF in P2 during Part 2. Furthermore, in Figure 6 In the example shown, during the period when the power of the high-frequency power RF increases, the frequency of the high-frequency power RF changes in the manner of its increase. Furthermore, in Figure 6 In the example shown, during the period when the power of the high-frequency power RF decreases, the frequency of the high-frequency power RF changes in a manner that decreases. Furthermore, in Figure 6 In the example shown, the frequency of the high-frequency power RF during the period of high power is higher than the frequency of the high-frequency power RF during the period of low power.

[0065] exist Figure 7 In the example shown, during the first period, P1 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 7 In the example shown, during the second period, P2 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 7 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during the first part and to stop supplying high-frequency power RF to P2 during the second part. That is, in Figure 7 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply pulses of high-frequency power RF to P1 during Part 1. Figure 7 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 7 In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner.

[0066] exist Figure 8 In the example shown, during the first period, P1 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 8 In the example shown, during the second period, P2 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 8 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during Part 1. Figure 8 In the example shown, the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second period P2 to a power level greater than 0 [W] and reduced from the power level of the high-frequency power RF in the first period P1. Figure 8 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 8 In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner. Figure 8 In the example shown, the frequency of the high-frequency power RF in P1 during Part 1 is lower than the frequency of the high-frequency power RF in P2 during Part 2.

[0067] exist Figure 9 In the example shown, during the first period, P1 is a pulsed negative DC voltage PV that is not applied to the base 18. Figure 9 In the example shown, during the second period, P2 is the period during which a pulsed, negative-polarity DC voltage PV is applied to the base 18. Figure 9 In the example shown, the control unit MC controls the high-frequency power supply 61 to supply high-frequency power RF to P1 during Part 1. Figure 9 In the example shown, the control unit MC controls the high-frequency power supply 61 to set the power level of the high-frequency power RF in the second period P2 to a power level reduced from the power level of the high-frequency power RF in the first period P1. Furthermore, in Figure 9 In the example shown, the control unit MC controls the high-frequency power supply 61 to change the power level of the high-frequency power RF during the first part period P1. Thus, the control unit MC can also control the high-frequency power supply 61 to change the power level of the high-frequency power RF more than once during at least one of the first part period P1 and the second part period P2.

[0068] exist Figure 9 In the example shown, during the first transition, the frequency of the high-frequency power RF changes in an increasing manner. Figure 9 In the example shown, during the second transition, the frequency of the high-frequency power RF changes in a decreasing manner. Figure 9 In the example shown, the frequency of the high-frequency power RF in P1 during Part 1 is lower than the frequency of the high-frequency power RF in P2 during Part 2. Furthermore, in Figure 9 In the example shown, during the period when the power of the high-frequency power RF increases, the frequency of the high-frequency power RF changes in a decreasing manner. Furthermore, in Figure 9 In the example shown, during the period when the power of the high-frequency power RF decreases, the frequency of the high-frequency power RF changes in a manner that increases. Furthermore, in Figure 9 In the example shown, the frequency of the high-frequency power RF during the period of high power is lower than the frequency of the high-frequency power RF during the period of low power. For example... Figure 9As shown in the example, the frequency of the high-frequency power RF can be changed more than once during at least one of the first period P1 and the second period P2. That is, the frequency of the high-frequency power RF can be varied during at least one of the first period P1 and the second period P2.

[0069] The following is for reference. Figure 10 . Figure 10 This is a flowchart illustrating a plasma processing method according to an exemplary embodiment. Figure 10 The plasma processing method shown (hereinafter referred to as "method MT") can be performed using the plasma processing apparatus 1 described above.

[0070] Method MT is performed with the substrate W placed on the electrostatic chuck 20. Method MT is performed to perform plasma treatment on the substrate W. In method MT, gas is supplied from the gas supply unit into the chamber 10. Then, the gas pressure in the chamber 10 is set to a specified pressure by the exhaust device 50.

[0071] In method MT, step ST1 is executed. In step ST1, a pulsed negative DC voltage PV is applied during period P. P A bias power supply 62 is periodically applied to the base 18.

[0072] Process ST2 is executed during the execution of process ST1. In process ST2, in order to reduce the power level of the reflected wave from the load of the high-frequency power supply 61, during period P... P The internal power supply is a high-frequency electrical RF that varies in frequency. Regarding the period P... P For the setting of the frequency of the high-frequency power RF corresponding to the phase within the circuit and examples, please refer to the above explanation and... Figures 2-9 Examples.

[0073] In one embodiment, high-frequency power RF can also be used in period P. P At least a portion of the first period P1 is supplied from the high-frequency power supply 61. In one embodiment, the period P... P The power level of the high-frequency power RF in the second part of P2 can also be set to a power level reduced from the power level of the high-frequency power RF in the first part of P1. The power level of the high-frequency power RF in the second part of P2 can also be 0 [W].

[0074] In one embodiment, the first period P1 may also be the period during which a pulsed negative DC voltage PV is applied to the base 18, and the second period P2 may also be the period during which the pulsed negative DC voltage PV is not applied to the base 18. In another embodiment, the first period P1 may also be the period during which the pulsed negative DC voltage PV is not applied to the base 18, and the second period P2 may also be the period during which the pulsed negative DC voltage PV is applied to the base 18.

[0075] The above descriptions of various exemplary embodiments are not limited to these exemplary embodiments, and various additions, omissions, substitutions, and modifications can be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0076] Another embodiment of the plasma processing apparatus may be a capacitively coupled plasma processing apparatus, different from plasma processing apparatus 1. Furthermore, yet another embodiment may be an inductively coupled plasma processing apparatus. Also, yet another embodiment may be an ECR (electron cyclotron resonance) plasma processing apparatus. Furthermore, yet another embodiment may be a plasma processing apparatus that generates plasma using surface waves such as microwaves.

[0077] Furthermore, in another embodiment, one or more bias electrodes can be provided within the body of the electrostatic chuck 20 included in the substrate support 16, and a bias power supply 62 can be connected to the bias electrode to supply a pulsed negative voltage. The bias electrode can be provided separately from the chuck electrode, or the chuck electrode can also be used as the bias electrode. Additionally, a high-frequency power supply 61 can be connected together with the bias power supply 62 to the bias electrode to supply high-frequency power (RF) to the bias electrode.

[0078] Furthermore, the period P P It can also consist of three or more partial periods, including a first partial period P1 and a second partial period P2. Period P P The durations of the three or more periods within a given period can be the same or different from each other. The power level of the high-frequency electrical RF in each of the three or more periods can be the same or set to a power level different from the power level of the high-frequency electrical RF in the preceding and following periods.

[0079] Furthermore, the pulsed negative DC voltage PV in Figures 2-9In the examples shown, there is a certain negative peak voltage value between the first transition period and the second transition period, but this is not limited to these examples. The pulsed negative DC voltage PV may also have multiple voltage values ​​between the first transition period and the second transition period.

[0080] As can be understood from the above description, the 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 present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit can be shown by the scope of the appended technical solutions.

Claims

1. A plasma processing apparatus, comprising: chamber; A substrate support has a base and an electrostatic chuck disposed on the base, and is configured to support and carry a substrate placed thereon in the cavity. A high-frequency power supply is configured to generate high-frequency power for the generation of plasma from the gas within the chamber. A bias power supply, electrically connected to the substrate support, is configured to periodically apply a pulsed negative DC voltage, i.e., a single voltage pulse, to the substrate support; and The control unit is configured to control the high-frequency power supply. In order to reduce the power level of the reflected wave from the load of the high-frequency power supply, the control unit controls the high-frequency power supply to supply high-frequency power with varying frequency within the period of the single voltage pulse applied to the substrate support from the bias power supply.

2. The plasma processing apparatus according to claim 1, wherein, The control unit controls the high-frequency power supply to supply the high-frequency power during at least a portion of the first part of the cycle, and sets the power level of the high-frequency power during the second part of the cycle to a power level that is reduced from the power level of the high-frequency power during the first part of the cycle.

3. The plasma processing apparatus according to claim 2, wherein, The first part of the period refers to the period during which the pulsed, negative-polarity DC voltage is applied to the substrate support. The second period is the period during which the pulsed negative DC voltage is not applied to the substrate support.

4. The plasma processing apparatus according to claim 2, wherein, The first period refers to the period during which the pulsed, negative-polarity DC voltage is not applied to the substrate support. The second part of the period is the period during which the pulsed, negative-polarity DC voltage is applied to the substrate support.

5. The plasma processing apparatus according to any one of claims 1 to 4, wherein, In order to reduce the power level of the reflected wave within the period, the control unit controls the high-frequency power supply to change the frequency of the high-frequency power supply according to the phase within the period.

6. A plasma processing method using a plasma processing device, The plasma processing device has the following features: chamber; A substrate support has a base and an electrostatic chuck disposed on the base, and is configured to support and carry a substrate placed thereon in the cavity. A high-frequency power supply configured to generate high-frequency electricity for the generation of plasma from the gas within the chamber; and The bias power supply is electrically connected to the substrate support. This plasma processing method is performed to process the substrate with the substrate placed on the electrostatic chuck. The plasma processing method includes: The process of periodically applying a pulsed negative DC voltage, i.e., a single voltage pulse, from the bias power supply to the substrate support; and In order to reduce the power level of the reflected wave from the load of the high-frequency power supply, a process of supplying the high-frequency power with a frequency variation to the substrate support during the period of the single voltage pulse from the bias power supply.

7. The plasma treatment method according to claim 6, wherein, The high-frequency power is supplied during at least a portion of the first period of the cycle. The power level of the high-frequency power during the second part of the cycle is set to a power level that is reduced from the power level of the high-frequency power during the first part of the cycle.

8. The plasma treatment method according to claim 7, wherein, The first part of the period refers to the period during which the pulsed, negative-polarity DC voltage is applied to the substrate support. The second period is the period during which the pulsed negative DC voltage is not applied to the substrate support.

9. The plasma treatment method according to claim 7, wherein, The first period refers to the period during which the pulsed, negative-polarity DC voltage is not applied to the substrate support. The second part of the period is the period during which the pulsed, negative-polarity DC voltage is applied to the substrate support.

10. The plasma processing method according to any one of claims 6 to 9, wherein, In order to reduce the power level of the reflected wave during the period, the frequency of the high-frequency power is changed according to the phase during the period.

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