Plasma processing apparatus and power supply system

Abstract

To improve the processing performance of plasma etching.SOLUTION: A plasma processing apparatus includes a plasma processing chamber, a substrate support, a source RF generator, and a bias RF generator. The substrate support is disposed in the plasma processing chamber. The source RF generator is coupled to the plasma processing chamber and generates a pulse source RF signal including a plurality of source cycles. Each source cycle has a source operating state and a source non-operating state. The bias RF generator is coupled to the substrate support, and generates a pulse bias RF signal. The pulse bias RF signal includes a plurality of bias cycles having the same pulse frequency as that of the plurality of source cycles, and each bias cycle has a bias operating state and a bias non-operating state. A transition timing to the bias operating state in each bias cycle is delayed with respect to a transition timing to the source operating state in the corresponding source cycle.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The following disclosure relates to a plasma processing apparatus and a power supply system. [Background technology]

[0002] Patent Document 1 discloses a technique for pulsing an RF (Radio Frequency) signal in an apparatus using inductively coupled plasma (ICP, also called transformer coupled plasma (TCP)). Patent Document 1 discloses, for example, synchronizing a source RF signal supplied to a coil and a bias RF signal supplied to a chuck so that their pulse sequences are reversed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2017 / 0040174 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can improve the processing performance of plasma etching. [Means for solving the problem]

[0005] A plasma processing apparatus according to one embodiment of the present disclosure includes a plasma processing chamber, a substrate support, a source RF generator, and a bias RF generator. The substrate support is disposed within the plasma processing chamber. The source RF generator is coupled to the plasma processing chamber and configured to generate a source RF signal to generate a plasma in the plasma processing chamber. The source RF signal has a zero power level during a first period of each cycle, a zero power level during a second period following the first period of each cycle, a first source power level greater than the zero power level during a third period following the second period of each cycle, a second source power level greater than the zero power level but different from the first source power level during a fourth period following the third period of each cycle, and a zero power level during a fifth period following the fourth period of each cycle. The bias RF generator is coupled to the substrate support and configured to generate the bias RF signal. The bias RF signal has a first bias power level greater than zero power level during a first period, a second bias power level greater than zero power level and different from the first bias power level during a second and third period, and a zero power level during a fourth and fifth period. [Effects of the Invention]

[0006] According to the present disclosure, the processing performance of plasma etching can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a conceptual diagram of the configuration of a plasma processing apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view showing an example of the configuration of the plasma processing apparatus of FIG. [Figure 3] FIG. 3 is a flowchart showing an example of the flow of plasma processing according to this embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a substrate to be processed by the plasma processing according to the embodiment. [Figure 5]FIG. 5 is a diagram showing an example of a waveform of an RF signal used for supplying radio frequency (RF) power in the plasma processing according to the embodiment. [Figure 6] FIG. 6 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the first example waveform of the RF signal. [Figure 7] FIG. 7 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the second example waveform of the RF signal. [Figure 8] FIG. 8 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the third example waveform of the RF signal. [Figure 9] FIG. 9 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the fourth example waveform of the RF signal. [Figure 10] FIG. 10 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to the first modification. [Figure 11] FIG. 11 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to the second modification. [Figure 12] FIG. 12 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to the third modification. [Figure 13] FIG. 13 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to the fourth modification. [Figure 14] FIG. 14 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to the fifth modification. [Figure 15] FIG. 15 is a flowchart showing an example of the flow of RF power supply in plasma processing according to this embodiment. [Figure 16] FIG. 16 is a flowchart showing another example of the flow of RF power supply in plasma processing according to this embodiment. [Figure 17] FIG. 17 is a diagram for explaining an example of a shape abnormality that occurs during etching. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a detailed description will be given of a plasma processing apparatus and a power supply system according to the present disclosure (hereinafter referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. Furthermore, the embodiments can be appropriately combined as long as the processing content is not contradictory. Furthermore, the same components in the following embodiments are designated by the same reference numerals, and redundant explanations will be omitted.

[0009] (Example of shape abnormalities that occur during etching) Before describing the embodiments, an example of a shape abnormality that occurs during etching of a silicon film will be described first. Fig. 17 is a diagram for explaining an example of a shape abnormality that occurs during etching of a silicon film.

[0010] In recent years, the technology of processing holes with high aspect ratios has been attracting attention in semiconductor manufacturing technology. One example is high aspect ratio contact (HARC). HARC is used in DRAM (Dynamic Random Access Memory) and 3D NAND. The aspect ratio of HARC used in DRAM is, for example, 45, while the aspect ratio of HARC used in 3D NAND is over 65.

[0011] As the aspect ratio of the hole increases, it becomes more difficult to form a hole that is straight in the vertical direction. For example, as shown in Figure 17(A), a phenomenon occurs in which the hole tapers toward the bottom. This phenomenon may be caused, for example, by the incident direction of ions in the plasma being oblique to the depth direction of the hole, making it difficult for ions to be transported to the bottom of the hole. Another possible cause is that ions may become trapped inside the hole, blocking the path of subsequent ions.

[0012] Furthermore, as shown in Figure 17(B), materials removed by etching and reaction products generated by the plasma may accumulate on the substrate. If such materials accumulate near the opening of the hole, the opening will be blocked, preventing etching from proceeding. Even if the opening is not completely blocked, it will be difficult for ions to reach the inside of the hole, causing the shape of the hole to become distorted and preventing etching from proceeding.

[0013] Furthermore, etching can sometimes remove the edges of the mask openings, distorting the direction of ions entering the holes and causing a phenomenon called bowing, in which the holes are distorted into a barrel shape when they hit the sidewalls of the holes, as shown in Figure 17(C).

[0014] As described above, the processing performance of high aspect ratio plasma processing is affected by the radicals and ions generated in the plasma and the reaction products generated by the plasma processing. Therefore, a technology that can individually control the reactive species, radicals, by-products, etc. generated depending on the progress of the plasma processing is desired.

[0015] (Embodiment) In the embodiment described below, RF (radio frequency) power used for plasma generation is applied in pulses to control various physical quantities, which are parameters of plasma processing, such as ion energy, ion incident angle, radical flux, ion flux, and amount of by-products.

[0016] The plasma processing apparatus according to the embodiment described below is an ICP apparatus. The control unit of the plasma processing apparatus according to the embodiment controls the RF power (source RF signal, source power) supplied to the coil (antenna) using a control signal. In one embodiment, high-density plasma is generated by supplying the source RF signal. The RF power can be supplied in a variety of ways. For example, the control unit of the plasma processing apparatus may switch power supply paths from multiple source RF generators based on a pre-prepared program to sequentially supply source powers of different power levels in pulses.

[0017] The period during which RF power is supplied to the coil is called an on (operating) period, and the period during which RF power supply to the coil is stopped is called an off (non-operating) period. The source RF signal has a first state corresponding to the on period, e.g., an on state (source on state), and a second state corresponding to the off period, e.g., an off state (source off state). The source RF signal is a pulse signal in which one period (source cycle) consists of an on period of the first state followed by an off period of the second state. The frequency of the source RF signal may be, for example, about 1 kHz to about 5 kHz.

[0018] Note that the source RF signal of the embodiment may transition to two or more levels (e.g., a first source power level and a second source power level) during the first state. For example, the first state of the source RF signal may have a first level at which a predetermined value of RF power is supplied to the coil and a second level at which a value of RF power lower than the first level is supplied to the coil. For example, the source RF signal may have a first level at which approximately 1000 watts of RF power is supplied to the coil and a second level at which approximately 250 watts of RF power is supplied to the coil. The RF power supplied at the second level may be approximately 100 watts or approximately 150 watts. The first level and the second level may be a high level and a low level, respectively.

[0019] The control unit also controls the RF power (bias RF signal, bias power) supplied to the lower electrode of the plasma processing apparatus using a control signal. In one embodiment, the supply of the bias RF signal causes ionic bonds to occur in a substrate placed above the lower electrode, generating reactive species and radicals. The supply of RF power can be realized in various ways. For example, based on a pre-prepared program, the control unit of the plasma processing apparatus may switch power supply paths from multiple bias RF generation units to sequentially supply pulsed bias power of different power levels.

[0020] The period during which RF power is supplied to the lower electrode is called an on period, and the period during which RF power supply to the lower electrode is stopped is called an off period. The bias RF signal has a first state, such as an on state (bias on state), corresponding to the on period, and a second state, such as an off state (bias off state), corresponding to the off period. The bias RF signal is a continuous pulse signal in which one cycle (bias cycle) consists of an on period of the first state followed by an off period of the second state. The frequency of the bias RF signal may be, for example, about 1 kHz to about 5 kHz.

[0021] Note that the bias RF signal of the embodiment may transition to two or more levels (e.g., a first bias power level and a second bias power level) during the first state. For example, the first state of the bias RF signal may have a first level at which a predetermined value of RF power is supplied to the lower electrode, and a second level at which a value of RF power lower than the first level is supplied to the lower electrode. For example, the bias RF signal may have a first level at which approximately 250 watts of RF power is supplied to the lower electrode, and a second level at which approximately 92.5 watts of RF power is supplied to the lower electrode. The first level and the second level may be a high level and a low level, respectively.

[0022] First, an example of the configuration of a plasma processing apparatus for performing plasma processing will be described below.

[0023] (Configuration example of plasma processing apparatus according to embodiment) Fig. 1 is a conceptual diagram of the configuration of a plasma processing apparatus according to an embodiment. Fig. 2 is a schematic vertical cross-sectional view showing an example of the configuration of the plasma processing apparatus of Fig. 1. A plasma processing apparatus 1 according to an embodiment will be described with reference to Figs. 1 and 2. The plasma processing apparatus 1 shown in Fig. 2 is a so-called inductively coupled plasma (ICP) apparatus, and generates inductively coupled plasma.

[0024] The plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply unit 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 10a and a sidewall 10b. The dielectric window 10a and the sidewall 10b define a plasma processing space 10s within the plasma processing chamber 10. The plasma processing apparatus 1 also includes a support 11, an edge ring 12, a gas introduction unit 13, and an antenna 14, which are disposed within the plasma processing space 10s. The support 11 includes a substrate support 11a and an edge ring support 11b. The edge ring support 11b is disposed to surround the outer periphery of the substrate support 11a. The antenna 14 is disposed above or at the top of the plasma processing chamber 10 (dielectric window 10a).

[0025] The substrate support 11a has a substrate support region and is configured to support a substrate on the substrate support region. In one embodiment, the substrate support 11a includes an electrostatic chuck and a lower electrode. The lower electrode is disposed below the electrostatic chuck. The electrostatic chuck functions as the substrate support region. Although not shown, in one embodiment, the substrate support 11a may also include a temperature control module configured to adjust at least one of the electrostatic chuck and the substrate to a target temperature. The temperature control module may include a heater, a flow path, or a combination thereof. A temperature control fluid such as a refrigerant or a heat transfer gas flows through the flow path.

[0026] The edge ring 12 is disposed on the upper surface of the peripheral edge of the lower electrode so as to surround the substrate W. The edge ring support 11b has an edge ring support region and is configured to support the edge ring 12 on the edge ring support region.

[0027] The gas inlet 13 is configured to supply at least one process gas from the gas supply 20 to the plasma processing space 10s. In one embodiment, the gas inlet 13 includes a central gas inlet 13a and / or a sidewall gas inlet 13b. The central gas inlet 13a is disposed above the substrate support 11a and is attached to a central opening formed in the dielectric window 10c. The sidewall gas inlet 13b is attached to a plurality of sidewall openings formed in the sidewall of the plasma processing chamber 10.

[0028] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply one or more process gases from respective gas sources 21 to the gas inlet through respective flow controllers 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include one or more flow modulation devices to modulate or pulse the flow rate of one or more process gases.

[0029] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10. The RF power supply 31 is configured to supply RF signals (RF power, e.g., a source RF signal and a bias RF signal) to the lower electrode and the antenna 14. This generates a plasma from at least one process gas supplied to the plasma processing space 10s. In one embodiment, the RF signal is pulsed. A pulsed RF signal, a pulsed RF power, a pulsed source RF signal, and a pulsed bias RF signal are examples of pulsed RF signals.

[0030] In one embodiment, the RF power supply 31 includes a source RF generator 31a and a bias RF generator 31b. The source RF generator 31a and the bias RF generator 31b are coupled to the plasma processing chamber 10. In one embodiment, the source RF generator 31a is coupled to the antenna 14, and the bias RF generator 31b is coupled to a lower electrode in the substrate support 11a. The source RF generator 31a is configured to generate at least one source RF signal. In one embodiment, the source RF signal has a frequency in the range of 27 MHz to 100 MHz. The generated source RF signal is provided to the antenna 14. The bias RF generator 31b is configured to generate at least one bias RF signal. The bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. The generated bias RF signal is provided to the lower electrode. In various embodiments, the amplitude of at least one of the source RF signal and the bias RF signal may be pulsed or modulated. Amplitude modulation may involve pulsing the RF signal amplitude between an on state and an off state, or between two or more different on states.

[0031] The power supply unit 30 may also include a DC power supply unit 32. In one embodiment, the DC power supply unit 32 is configured to apply at least one DC voltage to the lower electrode. In one embodiment, the at least one DC voltage may be applied to other electrodes, such as electrodes in an electrostatic chuck. In one embodiment, the DC signal may be pulsed. The DC power supply unit 32 may be provided in addition to the RF power supply unit 31 or may be provided instead of the bias RF generator unit 31b.

[0032] The antenna 14 includes one or more coils (ICP coils). In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0033] The exhaust system 40 may be connected to, for example, an exhaust port (gas outlet) provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure valve and a vacuum pump. The vacuum pump may include a turbomolecular pump, a roughing pump, or a combination thereof.

[0034] In one embodiment, the control unit (corresponding to the control device 50 in FIG. 2 ) processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, some or all of the control unit may be included in the plasma processing apparatus 1. The control unit may include, for example, a computer. The computer may include, for example, a processing unit (CPU: Central Processing Unit), a storage unit, and a communication interface. The processing unit may be configured to perform various control operations based on programs stored in the storage unit. The storage unit may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0035] (Plasma processing flow according to the embodiment) Fig. 3 is a flowchart showing an example of the flow of plasma processing according to the embodiment. The plasma processing shown in Fig. 3 can be performed in the plasma processing apparatus 1 shown in Figs. 1 and 2. Fig. 4 is a diagram showing an example of a substrate processed by the plasma processing according to the embodiment.

[0036] First, a substrate W is provided in the plasma processing chamber 10 (step S31). As shown in FIG. 4, the substrate W includes a base layer L1, an etching target layer (Si layer) L2, and a mask MK, which are formed in this order on a silicon substrate. A recess OP is formed in the substrate W in advance (see FIG. 4(A)). The recess OP may be formed inside the plasma processing apparatus 1. Next, the control unit controls the plasma processing apparatus 1 to supply etching gas from the gas supply unit 20 into the plasma processing chamber 10. The control unit also controls the plasma processing apparatus 1 to supply RF power from the RF power supply unit 31 (the source RF generation unit 31a and the bias RF generation unit 31b) to the lower electrode and the antenna 14 (coil). At this time, the RF power supply unit 31 supplies RF power at a level corresponding to the waveform of an RF signal to the lower electrode and the antenna 14. The waveform of the RF signal will be described later. The supply of RF power generates plasma from the gas supplied into the plasma processing chamber 10, and plasma etching is performed (step S32). The plasma etching removes the bottom of the recess OP formed in the mask MK of the substrate W, gradually deepening the recess OP (see FIG. 4B). Then, the control unit of the plasma processing apparatus 1 determines whether a predetermined processing time has elapsed (step S33). When the predetermined processing time has elapsed, the bottom of the recess OP reaches the base layer L1, resulting in the shape shown in FIG. 4C. If it is determined that the processing time has not elapsed (step S33, No), the control unit returns to step S32 and continues plasma etching. On the other hand, if it is determined that the processing time has elapsed (step S33, Yes), the control unit ends the processing.

[0037] The plasma processing apparatus 1 according to this embodiment supplies a source RF signal and a bias RF signal during plasma etching in step S32. The plasma processing apparatus 1 controls the amounts of ions and radicals in the plasma and by-products generated by plasma etching according to the waveforms of the source RF signal and the bias RF signal. Next, the waveforms of the source RF signal and the bias RF signal will be described.

[0038] (Example of RF signal waveform) FIG. 5 is a diagram showing an example of a waveform of an RF signal used for supplying RF power in the plasma processing according to the embodiment.

[0039] The timing diagram 100 shown in FIG. 5 is a timing diagram of the source power (source RF signal) P S and bias power (bias RF signal) P B The source power P S is the RF power supplied from the source RF generator 31a to the antenna (coil) 14. Also, the bias power P B is RF power supplied from the bias RF generator 31b to the lower electrode in the substrate support 11a. The source RF generator 31a controls the source power P S Generated source power P S is supplied to the coil. The bias RF generating unit 31b generates the bias power P B The generated bias power P S is supplied to the lower electrode.

[0040] In Figure 5, period 150 indicates one period of the source RF signal. Period 160 indicates one period of the bias RF signal. In the following explanation, unless there is a need to distinguish between them, periods 1501, 1502, ... will be collectively referred to as period 150, and periods 1601, 1602, ... will be collectively referred to as period 160. One period refers to the period from the rising edge of a pulse signal to the next rising edge, i.e., the sum of the on period and the off period. The source RF signal and the bias RF signal are pulse signals of the same frequency.

[0041] The source RF signal alternates between an on state (first state) in which RF power is supplied to the coil and an off state (second state) in which RF power is not supplied to the coil. When the source RF signal is in the on state, the source power P S is supplied to the coil. When the source RF signal is in the off state, no power is supplied to the coil, i.e., the supply of RF power to the coil is stopped.

[0042] The bias RF signal alternates between an ON state (first state) in which RF power is supplied to the lower electrode and an OFF state (second state) in which RF power is not supplied to the lower electrode. In the example of FIG. 5, when the bias RF signal is in the ON state, the bias power P B is supplied to the lower electrode. When the bias RF signal is in the off state, no power is supplied to the lower electrode, that is, the supply of RF power to the lower electrode is stopped.

[0043] In FIG. 5, the rising edge of the bias RF signal is delayed by a period D1 from the rising edge of the source RF signal. The bias RF signal rises while the source RF signal is in the off state after the source RF signal has transitioned from the on state to the off state. In this way, there is a difference of a period D1 between the timing at which the period of the source RF signal starts and the timing at which the period of the bias RF signal starts. In the example of FIG. 5, the bias-off state (t3) in the previous bias cycle is changed to the bias-on state P in the first bias cycle 1601. BL The transition timing to (t4) is the source-on state P SH 5. The source-off period partially overlaps with the bias-off period, as shown at t3 in FIG. 5. The bias-on period in the first bias cycle 1601 partially overlaps with the source-on period in the second source cycle 1502, as shown at t6 in FIG. 5.

[0044] Furthermore, the lengths of the on-period and off-period of the source RF signal are different from the lengths of the on-period and off-period of the bias RF signal. In the example of Figure 5, the duty ratio of the source RF signal (the ratio of the length of the on-period to one cycle) is approximately 40%. The duty ratio of the bias RF signal is approximately 60%. However, the duty ratios of the source RF signal and the bias RF signal are not limited to the above values. The source RF signal and the bias RF signal may also have the same duty ratio.

[0045] In this way, the source RF signal and the bias RF signal undergo state transitions independently. The timing of the state transition of the source RF signal and the power levels at the source and destination of the transition may be different from the timing of the state transition of the bias RF signal and the power levels at the source and destination of the transition.

[0046] Also, during a period T when neither the source RF signal nor the bias RF signal is supplied OFF and a period T during which both the source RF signal and the bias RF signal are supplied. ON There exists a source power P S and bias power P B The supply pattern will transition through the following five phases:

[0047] (1) Phase 1 (ST1 in Figure 5): The first phase is the parameter set {P S1 ,P B1 , t1}, where P S1 is the source power P delivered during the first phase S The value of P B1 is the bias power P supplied during the first phase B where t1 is the length of the first phase. Here, the following relationship holds: P S1 >0 P B1 >0 t1>0

[0048] In the first phase, the high power level PSH (first source power level) S is supplied to the coil, and a high power level P BH (second bias power level) B is supplied to the lower electrode. During the period t1 of the first phase, RF power is supplied to the upper and lower portions of the plasma processing apparatus 1 to generate plasma, and ions and radicals are generated in the plasma. During the etching process, etching progresses during the period t1.

[0049] (2) Phase 2 (ST2 in Figure 5): The second phase is the parameter set {P S2 ,P B2 , t2}, where P S2 is the source power P delivered during the second phase S The value of P B2 is the bias power P supplied during the second phase B where t2 is the length of the second phase. Here, the following relationship holds: P S1 >P S2 >0 P B1 =0 t2>0

[0050] In the second phase, the low power level P SL (second source power level) S is supplied to the coil, and the bias power P B The supply of RF power is stopped. The second phase corresponds to, for example, period t2 in FIG. 5. During period t2, RF power is supplied only to the upper portion of the plasma processing apparatus 1. Since RF power is not supplied to the lower electrode side, no force is generated that attracts ions to the lower electrode side. In addition, the amount of ions and radicals generated also decreases.

[0051] (3) Phase 3 (ST3 in Figure 5): The third phase is the parameter set {P S3 ,P B3, t3}, where P S3 is the source power P delivered during the third phase S The value of P B3 is the bias power P supplied during the third phase B t3 is the length of the third phase. Here, the following relationship holds: P S3 =P B3 =0 t3>0

[0052] In the third phase, the source power P S and bias power P B The supply of both ions and radicals stops. The third phase corresponds to, for example, period t3 in FIG. 5. During period t3, plasma generation in the plasma processing apparatus 1 stops, and the exhaust system 40 simultaneously evacuates the plasma processing space 10s. At this time, by-products generated by etching and remaining at the bottom of the recess (OP in FIG. 4) are exhausted. The amount of ions and radicals in the plasma processing space 10s also decreases.

[0053] (4) Phase 4 (ST4 in Figure 5): The fourth phase is the parameter set {P S4 ,P B4 , t4}, where P S4 is the source power P delivered during the fourth phase S The value of P B4 is the bias power P supplied during the fourth phase B t4 is the length of the fourth phase. Here, the following relationship holds: P S4 =0 P B1 >P B4 >0 t4>0

[0054] In the fourth phase, the source power P S The supply of power is stopped, and the low power level P BL (first bias power level)B During the fourth phase period t4, the supply of source power P S Since the bias power P is not supplied, plasma generation is not performed, but the ions generated in the first and second phases remain in the plasma processing space 10s. B The supply of ions attracts the ions to the bottom of the recess (OP in FIG. 4). Also, the incident angle of the ions becomes closer to perpendicular, which promotes perpendicular etching of the sidewall of the recess OP.

[0055] (5) Phase 5 (ST5 in Figure 5): The fifth phase is the parameter set {P S5 ,P B5 , t5}, where P S5 is the source power P delivered during the fifth phase S The value of P B5 is the bias power P supplied during the fifth phase B t5 is the length of the fifth phase. Here, the following relationship holds: P S5 =0 P B1 =P B5 >P B4 >0 t5>0

[0056] In the fifth phase, the source power P S The bias power P B The power level is Low power level P BL From High power level P BH Therefore, in the fifth phase, the ion energy in the plasma processing space 10s increases as a preparation for the first phase. The amount of radicals and by-products remains at the state where it was reduced in the third phase.

[0057] After the fifth phase, the source power P S and bias power P with high power level BThis cycle is repeated, and in the fifth phase, the bias power P B The first phase begins with the ion energy generated by applying the source power P S This generates ions and radicals. This accelerates the etching in the first phase and efficiently draws the ions to the bottom of the recess OP. In addition, by-products are exhausted in the third phase, which further accelerates the etching.

[0058] In this way, by using the source RF signal and bias RF signal having the pulse waveforms shown in Fig. 5, vertical etching can be achieved while controlling the states of ions, radicals, and by-products in the plasma processing space 10s. As a result, shape abnormalities caused by etching can be suppressed, and the processing performance of plasma etching can be improved.

[0059] In the example of Figure 5, the source power P S is the value P SH Then, during the on-state in the subsequent period t2, the value P SL Also, the bias power P B During the period t4, the value P BL Then, in the next period t5, the value P BH In this way, in the plasma processing method according to the embodiment, the on state of the source RF signal may be controlled at two levels (three levels including the off state) in order to control each physical quantity of the plasma. Also, in the plasma processing method according to the embodiment, the on state of the bias RF signal may be controlled at two levels (three levels including the off state). In this way, by varying the RF power values ​​applied to the coil and the lower electrode in a stepwise manner, it is possible to further finely adjust the plasma processing parameters.

[0060] In the example of FIG. 5, the following relationship holds: 0 <P SL <P SH 0 <P BL <P BH Source RF signal and bias RF signal frequency: 0.1kHz to 5kHz Source RF signal duty ratio: approx. 40% Bias RF signal duty ratio: approx. 60% P SH Length of period:P SL Length of period = 1:3 P BH Length of period:P BL Length of period = 1:2 t1:t2:t3:t4:t5=1:3:1:4:1 However, this embodiment is not limited to the case where the above relationship holds, and can also be applied to other relationships, which will be described later as modified examples.

[0061] 6 to 9 are diagrams for explaining changes in physical quantities in the plasma processing chamber 10 according to exemplary waveforms of the RF signal. Changes in physical quantities according to the waveforms of the RF signal will be explained with reference to FIGS.

[0062] Waveform Example 1 in FIG. 6 includes a "first phase" in which source power and bias power are supplied simultaneously, a "second phase" in which only source power is supplied, and a "fourth phase" in which only bias power is supplied. Waveform Example 1 differs from the waveform examples of the above embodiment in that it does not include a "third phase" in which RF power is not supplied and a "fifth phase" in which the bias power power level fluctuates before the rising edge of the source RF signal. In the case of Waveform Example 1, the ion flux, radical flux, and ion energy all increase in the first phase, and the amount of by-products also increases. Subsequently, in the second phase, all of these amounts gradually decrease. The supply of bias power is stopped, and the ion energy becomes nearly zero. In the fourth phase, the supply of bias power increases the ion energy compared to the first phase. On the other hand, the ion flux, radical flux, and amount of by-products do not change significantly from the second phase.

[0063] Waveform example 2 in FIG. 7 is generally similar to waveform example 1 in FIG. 6. However, the bias power value (P BM ) is the bias power value (P BL ) is increased compared to the case of Waveform Example 1 in FIG. 7. In the example of FIG. 7, the ion flux, radical flux, and amount of by-products are roughly the same as in Waveform Example 1 in FIG. 6. However, the ion energy in the fourth phase is increased compared to Waveform Example 1 (C1 in FIG. 7). Note that in FIG. 7C, the change in ion energy in the case of FIG. 7A is shown on the same dashed line as in FIG. 6C, with only the parts that differ from FIG. 6C being shown by a thick dashed line C1.

[0064] Waveform Example 3 in Figure 8 has a longer first phase than Waveform Example 1 in Figure 6, and a correspondingly shorter second phase. In the example in Figure 8, the amount of ion flux and radical flux increases throughout the first and second phases compared to the example in Figure 6 (C2 and C3 in Figure 8). On the other hand, there is no significant change in the ion energy and the amount of by-products. Note that, like C1 above, the thick dashed lines C2 and C3 indicate only the parts that are different from Figure 6.

[0065] Waveform example 4 in FIG. 9 differs from waveform example 1 in FIG. 6 in that a fifth phase is provided. The power level of the fifth phase is the power level P BL From P BH In the example of FIG. 9, the ion flux, radical flux, and amount of by-products are almost the same as those in the waveform example 1 of FIG. 6. As for the ion energy, the bias power P B The thick dashed line C4 in Figure 9 shows only the parts that are different from (D) in Figure 6.

[0066] When etching was performed using the RF power waveforms shown in FIGS. 6 to 9, the fluctuations in the dimensions from the top to the bottom of the recess (critical dimension) were larger in Waveform Example 1 and Waveform Example 3 than in Waveform Example 2. That is, when a slightly high level of bias power was supplied, as in the fourth phase of Waveform Example 2, holes of more uniform size in the vertical direction were formed during deep hole etching. On the other hand, when the ratio between the length of the first phase and the length of the second phase was changed, as in Waveform Example 3, mask wear was reduced and selective etching of the target film was achieved. This shows that the state of ions and radicals in the plasma processing space 10s, particularly near the substrate to be processed, changes depending on the RF power waveform, affecting the performance of the plasma processing. Therefore, the performance of the plasma processing, that is, the shape of the pattern formed by the plasma processing, can be controlled by adjusting the waveform of the RF signal.

[0067] 6 to 9 do not include the third phase of this embodiment, i.e., the phase in which RF power is not supplied to either the coil or the lower electrode. By introducing the third phase in which RF power is not supplied, the amount of by-products in the plasma processing space 10s can be further reduced, and the etching accuracy in the vertical direction can be improved.

[0068] However, this embodiment is not limited to the waveforms shown in Fig. 5, and similar effects can be obtained by using modified examples. Modified examples 1 to 5 will be described below with reference to Figs.

[0069] (Variation 1) 10 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in the plasma processing according to Modification 1. A timing diagram 200 shown in FIG. S and bias power P B First, when the period t1 starts, the source power P SH and bias power P BH During the period t1, the source power P SH and bias power P BHThen, in the period t3, the source power P S and bias power P B The supply of both will be stopped (period T OFF ) Next, in the period t4, the bias power P BH Then, at the timing of the next period 1502, the supply of source power P SH The supply of source power P SH and bias power P BH are applied in superposition (period T ON ).

[0070] Unlike the example waveforms of FIG. 5, the timing diagram 200 of FIG. 10 shows the second phase, i.e., the source power P S The supply to the coil continues, and the bias power P B 10. Also, the timing diagram 200 of FIG. 10 shows the fifth phase, that is, the phase in which the supply of the source power P S Before supplying bias power P B Therefore, Modification 1 can be applied to pattern formation suitable for starting the exhaust of by-products (third phase) without adjusting the amount of ions or radicals. Modification 1 can also be applied to cases where it is not necessary to generate ion energy before plasma generation.

[0071] (Variation 2) 11 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to Modification 2. In a timing diagram 210 shown in FIG. 11, first, in a period t1, the source power P SH and bias power P BH In the next period t2, the source power P S The level of P SH From P SM When the period t2 starts, the bias power P BH Next, in the period t3, the supply of the source power P SM Therefore, during the period t3, the supply of the source power P S and bias power PB Neither of these is supplied (period T OFF ) Then, in the period t4, the bias power P BM During the period t4, the supply of level P BM Bias power P B Then, in the period t5, the bias power P B The level of BM From P BH Then, the bias power P BH The supply of power continues, and in the next period 1502, the source power P SH is supplied, and the source power P SH and bias power P BH are supplied in a superimposed manner (period T ON ).

[0072] Compared with the waveform example of FIG. 5, the source power P S The level of P SH and P SM The difference is that the source power P S The level of is Level P SH , P SM , P SL In addition, in the second modification, the bias power P B The level of P BH and P BM The difference from the waveform example in Figure 5 is that the bias power P B The level of is Level P BH , P BM , P BL In the second modification, the source power P S and bias power P B The ON state of the is set to two levels, with the lower of the two levels being set to a higher level than in the example of Figure 5.

[0073] For example, if it is desired to maintain the electron density Ne, radical density Nr, electron temperature Te, ion energy εi, etc. at high levels before and after the third phase in which by-products are exhausted, the source power P S and bias power P B It is advisable to set the levels of the multiple ON states of the above to be high.

[0074] In the second modification, the rising edge of the bias RF signal is delayed by a period D1 from the rising edge of the source RF signal, as in the waveform example of FIG. S and bias power P B In the period T when neither of the above is supplied OFF Also, the source power P S and bias power P B During the period T ON There exists a period T ON is the period from the time when the source RF signal rises to the time when the bias RF signal falls.

[0075] (Variation 3) 12 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to Modification 3. In a timing diagram 220 shown in FIG. 12, first, in a period t1, the source power P SH and bias power P BM Next, in a period t2, the source power P S The level of P SH From P SM In addition, in the period t2, the bias power P BM Next, in the period t3, the supply of the source power P SM During the period t3, the supply of the source power P S and bias power P B Neither of these is provided (T OFF ) Then, in the period t4, the bias power P BH During the period t4, the supply of level P BH Bias power P B Then, in the period t5, the bias power PB The level of BH From P BM Then, the bias power P BM The supply of power continues, and when period 1502 starts, the source power P SH is supplied, and the source power P SH and bias power P BM are supplied in a superimposed manner (period T ON ).

[0076] The third modification is generally similar to the second modification in FIG. 11. However, the third modification has the following difference: the bias power P B The order of transition of the levels of the bias power P B The level of BH and during period t4, P BM and during the period t5, P BH In contrast, in the third modification, the bias power P B The level of BM and during period t4, P BH and during the period t5, P BM In the second modification, the bias power P B The level of the bias power P changes from the first phase to the fifth phase in the order of high level, off state, low level, and high level. B The level of changes from the first phase to the fifth phase in the order of low level, off state, high level, and low level.

[0077] For example, in the case of plasma processing suitable for increasing the ion energy in the third phase to attract many ions to the bottom of the recess OP, the waveform of the third modification example is suitable.

[0078] (Variation 4) 13 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to Modification 4. In a timing diagram 230 shown in FIG. 13, first, in a period t1, the source power P SM and bias power P BHNext, in a period t2, the source power P S The level of P SM From P SH In addition, in the period t2, the bias power P BH Next, in a period t3, the supply of the source power P SH During the period t3, the supply of the source power P S and bias power P B Neither of these is provided (T OFF ) Then, in the period t4, the bias power P BM During the period t4, the supply of level P BM Bias power P B Then, in the period t5, the bias power P B The level of BM From P BH Then, the bias power P BH The supply of power continues, and in period 1502, the source power P SM is supplied, and the source power P SM and bias power P BH are supplied in a superimposed manner (period T ON ).

[0079] The fourth modification is generally similar to the second modification in FIG. 11. However, the fourth modification is different from the second modification in FIG. S The order of transition of the levels of the source power P S The level of SH and in period t2, P SM In contrast, in the third modification, the bias power P B The level of SM and in period t2, P SH In the second modification, the source power P S The level of the source power P changes from high to low to off from the first phase to the third phase, and does not change from the third phase to the fourth phase. SThe level of changes from low to high to off from the first phase to the third phase, and does not change from the third phase to the fourth phase.

[0080] Variation 4 is suitable for, for example, a process in which it is preferable to increase the amount of ions and radicals gradually rather than suddenly in the first phase.

[0081] (Variation 5) 14 is a diagram showing an example of the waveform of an RF signal used for supplying RF power in plasma processing according to Modification 5. In a timing diagram 240 shown in FIG. 14, first, in a period t1, the source power P SM and bias power P BM Next, in period t2, the source power P S The level of P SM From P SH In addition, in the period t2, the bias power P BM Next, in the period t3, the supply of the source power P SH During the period t3, the supply of the source power P S and bias power P B Neither of these is provided (T OFF ) Then, in the period t4, the bias power P BH During the period t4, the supply of level P BH Bias power P B Then, in the period t5, the bias power P B The level of BH From P BM Then, the bias power P BM The supply of power continues, and in period 1502, the source power P SM is supplied, and the source power P SM and bias power P BM are supplied superimposed (T ON ).

[0082] The fifth modification is the bias power P B and the source power P SThe bias power P B From the first phase to the fifth phase, the source power P S changes from the first phase to the fifth phase in the order of low level (first phase), high level (second phase), and off state (third to fifth phases). Therefore, the waveform of the fifth modification changes from the first phase to the fifth phase in the order of {P S ,P B} is {P SM ,P BM}{P SH ,P BOFF}, {P SOFF ,P BOFF}, {P SOFF ,P BH}{P SOFF ,P BM}. In this case, when the ON state in one waveform includes only two levels, one is called a high level and the other a low level, and is not called a middle level. Also, the source power P S The off state of P SOFF , bias power P B The off state of P BOFF and displays:

[0083] Modification 5 is suitable for a process in which it is preferable to first increase the ion energy in the fourth phase and then decrease it before etching.

[0084] (RF power supply flow) 15 is a flowchart showing an example of the flow of RF power supply in plasma processing according to this embodiment. A flow 1500 shown in FIG. 15 is executed, for example, in step S32 of FIG.

[0085] First, under the control of the control unit, the RF power supply unit 31 executes the first phase of RF power supply (step S1510). The first phase of RF power supply is executed based on a first set of processing parameters {PS1 ,P B1 , t1}, where P S1 >0 and P B1 >0, t1>0.

[0086] Next, under the control of the control unit, the RF power supply unit 31 executes the second phase of RF power supply (step S1520). The second phase of RF power supply is executed based on the second set of processing parameters {P S2 ,P B2 , t2}, where P S2 >0 and P B2 =0, t2≧0.

[0087] Next, under the control of the control unit, the RF power supply unit 31 executes the third phase of RF power supply (step S1530). The third phase of RF power supply is executed based on a third set of processing parameters {P S3 ,P B3 , t3}, where P S3 =0 and P B3 =0, t3>0.

[0088] Next, under the control of the control unit, the RF power supply unit 31 executes the fourth phase of RF power supply (step S1540). The fourth phase of RF power supply is executed based on the fourth set of processing parameters {P S4 ,P B4 , t4}, where P S4 =0 and P B4 >0,t4>0.

[0089] Next, under the control of the control unit, the RF power supply unit 31 executes the fifth phase of RF power supply (step S1550). The fifth phase of RF power supply is executed based on the fifth set of processing parameters {P S5 ,P B5 , t5}, where P S5 =0 and P B5 >0, t5≧0.

[0090] Steps S1510 to S1540 are executed as one cycle. After step S1540, the process may return to step S1510 and the cycle may be executed again.

[0091] 16 is a flowchart showing another example of the flow of RF power supply in plasma processing according to the embodiment. A flow 1600 shown in FIG. 16 is executed, for example, in step S32 of FIG.

[0092] First, under the control of the control unit, the RF power supply unit 31 supplies the source power P S At the same time, bias power P B As a result, plasma is generated in the plasma processing space 10s. The plasma contains ions and radicals (step S1610).

[0093] Next, under the control of the control unit, the RF power supply unit 31 supplies a bias power P B Also, the RF power supply unit 31 stops the supply of the source power P S The RF power supply 31 varies the value of the source power P S In this way, the RF power supply unit 31 adjusts the amount of ions and radicals contained in the plasma in the plasma processing space 10s (step S1620).

[0094] Next, under the control of the control unit, the RF power supply unit 31 supplies a bias power P B The source power P to the coil remains turned off. S The supply of the gas is stopped. Then, the exhaust system 40 exhausts the plasma processing space 10s, thereby reducing the amount of by-products in the plasma processing space 10s (step S1630).

[0095] Next, under the control of the control unit, the RF power supply unit 31 supplies a bias power P B It supplies the source power P SThe bias power P B An attractive force to the lower electrode is generated by the electric field (step S1640).

[0096] Steps S1610 to S1640 are executed as one cycle. After step S1640, the process may return to step S1610 and the cycle may be executed again.

[0097] The above-described embodiment and modified examples may be partially modified as appropriate. Possible modified embodiments are described below.

[0098] (Other embodiments) Source power P S may be alternating current (AC) power. Also, the source power P S The source power P may be either radio frequency (RF) power or very high frequency (VHF) power. S may be, for example, RF power in the range of about 60 MHz to about 200 MHz. S may be, for example, RF power in the range of about 25 MHz to about 60 MHz. S may be, for example, 27 MHz. In this embodiment, the source power P S generates an inductively coupled plasma (ICP). The source power P S For example, the plasma is generated by coupling with a helical antenna.

[0099] Bias power P B may be an alternating current (AC) power. Also, the bias power P B may be a direct current (DC) pulsed power. B The bias power P may be any of RF (Radio Frequency) power, HF (High Frequency) power, and MF (Medium Frequency) power. B For example, the bias power P may be a power having a frequency in the range of about 200 kHz to about 600 kHz.B may be, for example, 400 kHz. B may be, for example, a power in the range of about 600 kHz to about 13 MHz.

[0100] Source power P S and bias power P B may each be applied as a single pulse or as a series of pulses in each period. For example, in the first phase, the source power P S1 Similarly, the bias power P applied during the period t2 may be a single pulse or a continuous pulse. B2 may be a single pulse or a series of pulses.

[0101] The duty ratios of the source RF signal and the bias RF signal can be set independently within a range from about 3% to about 90%.

[0102] For example, in the case of a three-level waveform, the duty ratio of the source RF signal in the ON state at high level can be set within a range of approximately 5% to approximately 50%, the duty ratio of the source RF signal in the ON state at low level can be set within a range of approximately 0% to approximately 45%, and the duty ratio of the source RF signal in the OFF state can be set within a range of approximately 5% to approximately 90%.

[0103] The duty ratio of the bias RF signal in the ON state at high level can be set within a range of approximately 5% to approximately 50%, the duty ratio of the bias RF signal in the ON state at low level can be set within a range of approximately 0% to approximately 45%, and the duty ratio of the bias RF signal in the OFF state can be set within a range of approximately 5% to approximately 90%.

[0104] The length of the period during which the source RF signal and the bias RF signal are simultaneously in the off state can be set within a duty ratio range of about 5% to about 90%. This period can be set, for example, within a range of about 0 microseconds to about 500 microseconds, more preferably within a range of about 10 microseconds to about 50 milliseconds. This period may also be set within a duty ratio range of about 10% to about 50% for the source RF signal and the bias RF signal.

[0105] Gases are supplied to the plasma processing chamber 10 at flow rates selected according to a predetermined plasma process. Gases are supplied to the plasma processing chamber 10 at substantially the same flow rates throughout one cycle, including a first phase, a second phase, a third phase, a fourth phase, and a fifth phase. The supplied gases may include, for example, hydrogen bromide (HBr). The supplied gases may also include, for example, rare gases such as helium (He) and argon (Ar). The supplied gases may also include, for example, oxygen (O), tetrafluoromethane (CF), nitrogen trifluoride (NF), sulfur hexafluoride (SF), chlorine (Cl), tetrachloromethane (CCl), etc.

[0106] By-products generated during plasma processing according to embodiments may be compounds containing one or more elements present in the gas and substrate compositions within the plasma processing chamber 10. For example, when using a silicon substrate with HBr gas, by-products containing SiBrx may be formed. Other by-products may also be formed, including silicon-containing residues such as silicon fluorides (SiFx) and silicon chlorides (SiClx), and carbon-containing residues such as fluorocarbons (CFx) and hydrofluorocarbons (CHxFy) (in the case of processes using photoresists, organic films, or precursors).

[0107] (Effects of the embodiment) As described above, the plasma processing apparatus according to the embodiment includes a plasma processing chamber, a substrate support, a source RF generator, and a bias RF generator. The substrate support is disposed within the plasma processing chamber. The source RF generator is coupled to the plasma processing chamber and configured to generate a pulsed source RF signal including a plurality of source cycles. Each source cycle has a source active state during a source active period and a source inactive state during a source inactive period following the source active period. The bias RF generator is coupled to the substrate support and configured to generate a pulsed bias RF signal. The pulsed bias RF signal has a plurality of bias cycles having the same pulse frequency as the plurality of source cycles. Each bias cycle has a bias active state during a bias active period and a bias inactive state during a bias inactive period following the bias active period. The transition timing to the bias active state in each bias cycle is delayed relative to the transition timing to the source active state in the corresponding source cycle. The source off period overlaps with the bias inactive period. The bias active period in each bias cycle overlaps with the source active period in the next source cycle. In this way, the plasma processing apparatus supplies RF signals so that the periods of the pulsed source RF signal and the pulsed bias signal are shifted. The plasma processing apparatus also supplies RF signals so that the bias operation period lasts across two periods of the pulsed source RF signal. This allows the plasma processing apparatus to precisely control the ion energy generated during plasma etching, improving plasma etching performance. By shifting the source operation period and the bias operation period, the plasma processing apparatus can also set a higher power level to be supplied at the rising edge of the pulsed source RF signal (at the start of a period). This allows the plasma processing apparatus to achieve efficient plasma etching.

[0108] As described above, in the plasma processing apparatus according to the embodiment, the source operating state may have at least two source power levels, and the bias operating state may have at least two bias power levels.

[0109] As described above, in the plasma processing apparatus according to the embodiment, the source operating state may have a first source power level and a second source power level subsequent to the first source power level. The bias operating state may have a first bias power level and a second bias power level subsequent to the first bias power level. The pulsed bias RF signal may transition to the bias operating state during a source non-operating period in each source cycle.

[0110] As described above, in the plasma processing apparatus according to the embodiment, the bias RF signal may transition from the first bias power level to the second bias power level during the source non-operating period in each source cycle.

[0111] As described above, in the plasma processing apparatus according to the embodiment, the transition from the first source power level to the second source power level in each source cycle may be substantially synchronized with the transition from the bias-on state to the bias-off state in each bias cycle.

[0112] As described above, in the plasma processing apparatus according to the embodiment, the first source power level may be greater than the second source power level.

[0113] As described above, in the plasma processing apparatus according to the embodiment, the first source power level may be lower than the second source power level.

[0114] As described above, in the plasma processing apparatus according to the embodiment, the second bias power level may be greater than the first bias power level.

[0115] As described above, in the plasma processing apparatus according to the embodiment, the second bias power level may be lower than the first bias power level.

[0116] The plasma processing method according to the above embodiment may be a plasma processing method used in a plasma processing apparatus. The plasma processing apparatus may include a plasma processing chamber, an antenna, a first RF generator, a substrate support, and a second RF generator. The antenna may be located above the plasma processing chamber. The first RF generator may be coupled to the antenna and generate a first RF power. The substrate support may be located within the plasma processing chamber. The second RF generator may be coupled to the substrate support and generate a second RF power. The plasma processing method may include, during a first period, supplying the first RF power to the antenna and supplying the second RF power to the substrate support. The plasma processing method may also include, during a second period after the first period, supplying the first RF power to the antenna and stopping the supply of the second RF power to the substrate support. The plasma processing method may also include, during a third period after the second period, stopping the supply of the first RF power to the antenna and stopping the supply of the second RF power to the substrate support. The plasma processing method may also include the step of supplying the second RF power to the substrate support without supplying RF power to the antenna in a fourth period after the third period.The plasma processing method may then repeatedly perform each step.

[0117] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the spirit and scope of the appended claims. For example, the above-described embodiments have been described using an inductively coupled plasma apparatus as an example of a plasma processing method. However, the disclosed technology is not limited thereto and can be applied to plasma processing methods using other plasma apparatuses. For example, a capacitively coupled plasma (CCP) apparatus may be used instead of an inductively coupled plasma apparatus. In this case, the capacitively coupled plasma apparatus includes two opposing electrodes disposed within a plasma processing chamber. In one embodiment, one electrode is disposed within a substrate support and the other electrode is disposed above the substrate support. In this case, one electrode functions as a lower electrode and the other electrode functions as an upper electrode. The source RF generator 31a and the bias RF generator 31b are coupled to at least one of the two opposing electrodes. In one embodiment, the source RF generator 31a is coupled to the upper electrode, and the bias RF generator 31b is coupled to the lower electrode. The source RF generator 31a and the bias RF generator 31b may be coupled to the lower electrode. [Explanation of symbols]

[0118] 1. Plasma processing equipment 10 Plasma Processing Chamber 10a Dielectric window 10b side wall 10s Plasma treatment space 11 Support part 11a Board support part 11b Edge ring support 12 Edge Ring 13 Gas inlet 13a Central gas injection section 13b Sidewall gas injection section 14 Antenna 20 Gas supply unit 21 Gas Source 22 Flow Controller 30 Power supply section 31 RF power supply section 31a Source RF generation section 31b Bias RF generation section 32 DC power supply 40 Exhaust System W substrate

Claims

1. a plasma processing chamber; a substrate support disposed within the plasma processing chamber; a source RF generator coupled to the plasma processing chamber and configured to generate a source RF signal to generate a plasma in the plasma processing chamber, the source RF signal having a zero power level during a first period of each cycle, a zero power level during a second period of each cycle following the first period of each cycle, a first source power level greater than the zero power level during a third period of each cycle following the second period of each cycle, a second source power level greater than the zero power level and different from the first source power level during a fourth period of each cycle following the third period of each cycle, and a zero power level during a fifth period of each cycle following the fourth period of each cycle; a bias RF generator coupled to the substrate support and configured to generate a bias RF signal, the bias RF signal having a first bias power level greater than a zero power level during the first time period, a second bias power level greater than a zero power level and different from the first bias power level during the second and third time periods, and a zero power level during the fourth and fifth time periods; A plasma processing apparatus comprising:

2. The plasma processing apparatus of claim 1 , wherein the first source power level is greater than the second source power level.

3. 3. The plasma processing apparatus according to claim 1, wherein the first bias power level is lower than the second bias power level.

4. 3. The plasma processing apparatus according to claim 1, wherein the first bias power level is greater than the second bias power level.

5. The plasma processing apparatus of claim 1 , wherein the first source power level is less than the second source power level.

6. The plasma processing apparatus of claim 5 , wherein the first bias power level is less than the second bias power level.

7. The plasma processing apparatus of claim 5 , wherein the first bias power level is greater than the second bias power level.

8. A power supply system for use in a plasma processing apparatus, a source RF generator configured to generate a source RF signal, the source RF signal having a zero power level during a first period of each cycle, having a zero power level during a second period of each cycle following the first period of each cycle, having a first source power level greater than the zero power level during a third period of each cycle following the second period of each cycle, having a second source power level greater than the zero power level and different from the first source power level during a fourth period of each cycle following the third period of each cycle, and having a zero power level during a fifth period of each cycle following the fourth period of each cycle; a bias RF generator configured to generate a bias RF signal, the bias RF signal having a first bias power level greater than a zero power level during the first time period, a second bias power level greater than a zero power level and different from the first bias power level during the second and third time periods, and a zero power level during the fourth and fifth time periods; A power supply system comprising:

9. 9. The power system of claim 8, wherein the first source power level is greater than the second source power level.

10. 10. The power supply system of claim 8 or claim 9, wherein the first bias power level is less than the second bias power level.

11. 10. The power supply system of claim 8 or claim 9, wherein the first bias power level is greater than the second bias power level.

12. 9. The power system of claim 8, wherein the first source power level is less than the second source power level.

13. 13. The power system of claim 12, wherein the first bias power level is less than the second bias power level.

14. 13. The power system of claim 12, wherein the first bias power level is greater than the second bias power level.

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