Plasma processing apparatus and power supply system

Abstract

This invention aims to improve the processing performance of plasma etching. The plasma processing apparatus of this invention includes: a plasma processing chamber; a substrate support; a plasma source RF generation unit; and a bias RF generation unit. The substrate support is disposed within the plasma processing chamber. The plasma source RF generation unit is coupled to the plasma processing chamber and generates a pulsed plasma source RF signal comprising multiple plasma source cycles. Each plasma source cycle has: a plasma source operating state; and a plasma source inoperable state. The bias RF generation unit is coupled to the substrate support and generates a pulsed bias RF signal. The pulsed bias RF signal has multiple bias cycles, each having the same pulse frequency as the multiple plasma source cycles. Each bias cycle has: a bias operating state; and a bias inoperable state. The transition timing towards the bias operating state in each bias cycle is delayed relative to the transition timing towards the plasma source operating state in the corresponding plasma source cycle.

Description

Technical Field

[0001] The present invention relates to a plasma processing device and a power supply system. Prior Art

[0002] Patent Document 1 discloses a technique for pulsing an RF (Radio Frequency) signal using an inductively coupled plasma (ICP) device (also known as transformer coupled plasma (TCP)). For example, Patent Document 1 discloses synchronizing the plasma source RF signal supplied to the coil and the bias RF signal supplied to the chuck so that their pulse sequences are in opposite directions. [Prior Art Literature] [Patent Document]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0040174 Summary of the Invention

[0004] [Problems to be Solved by the Invention] The present invention provides a technology for improving the processing performance of plasma etching. [Means for solving the problem]

[0005] According to one aspect of the present invention, a plasma processing apparatus comprises: a plasma processing chamber; a substrate support; a plasma source RF generator; and a bias RF generator. The substrate support is disposed within the plasma processing chamber. The plasma source RF generator is coupled to the plasma processing chamber and generates a pulsed plasma source RF signal comprising a plurality of plasma source cycles. Each plasma source cycle comprises: a plasma source operating state between plasma source operating periods; and a plasma source non-operating state between plasma source non-operating periods following each plasma source operating period. The bias RF generator is coupled to the substrate support and generates a pulsed bias RF signal. The pulsed bias RF signal comprises a plurality of bias cycles having the same pulse frequency as the plurality of plasma source cycles. Each bias cycle comprises: a bias operating state between bias operating periods; and a bias non-operating state between bias non-operating periods following each bias operating period. The migration timing toward the bias operation state in each bias cycle is delayed relative to the migration timing toward the plasma source operation state in the corresponding plasma source cycle. The aforementioned plasma source non-operation period overlaps with the aforementioned bias non-operation period, and the bias operation period in each bias cycle overlaps with the plasma source operation period in the next plasma source cycle. [Effects of the Invention]

[0006] According to the present invention, the processing performance of plasma etching can be improved. Simple diagram description

[0007] [Fig. 1] Fig. 1 is a conceptual diagram of the structure of a plasma processing apparatus according to an embodiment. [Figure 2] Figure 2 is a schematic longitudinal sectional view showing an example of the structure of the plasma processing device in Figure 1. [Fig. 3] Fig. 3 is a flow chart showing an example of the flow of plasma processing according to an embodiment. [Fig. 4] Fig. 4(A) to (C) are diagrams showing an example of a substrate processed by plasma processing according to an embodiment. [Fig. 5] Fig. 5 is a diagram showing an example of a waveform of a high-frequency (RF) signal used for supplying RF power in plasma processing according to an embodiment. [Figure 6] Figures 6(A) to 6(E) are diagrams used to illustrate changes in physical quantities within a plasma processing chamber corresponding to Example 1 of the RF signal waveform. [Figure 7] Figures 7(A) to 7(E) are diagrams used to illustrate changes in physical quantities within a plasma processing chamber corresponding to Example 2 of the RF signal waveform. [Figure 8] Figures 8(A) to 8(E) are diagrams used to illustrate changes in physical quantities within a plasma processing chamber corresponding to Example 3 of the RF signal waveform. [Figure 9] Figures 9(A) to 9(E) are diagrams used to illustrate changes in physical quantities within a plasma processing chamber corresponding to Example 4 of the RF signal waveform. [Figure 10] Figure 10 is a diagram showing an example of the waveform of an RF signal used for RF power supply in plasma processing in Modification Example 1. [Figure 11] Figure 11 is a diagram showing an example of the waveform of an RF signal used for RF power supply in plasma processing in Modification Example 2. [Figure 12] Figure 12 is a diagram showing an example of the waveform of the RF signal used for RF power supply in plasma processing in Modification Example 3. [Figure 13] Figure 13 is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modification Example 4. [Figure 14] Figure 14 is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modification Example 5. [Fig. 15] Fig. 15 is a flow chart showing an example of the process of RF power supply for plasma processing according to an embodiment. [Fig. 16] Fig. 16 is a flow chart showing an example of the process of RF power supply for plasma processing according to an embodiment. [Figure 17] Figures 17 (A) to (C) are diagrams used to illustrate examples of shape abnormalities generated during etching. Implementation Method

[0008] Below, embodiments for implementing the plasma processing apparatus and plasma processing method according to the present invention (hereinafter referred to as "embodiments") are described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, the various embodiments may be combined as appropriate within the scope of the treatment content. Identical components in the various embodiments below are denoted by the same reference numerals, and duplicate descriptions will be omitted.

[0009] (Example of shape abnormality caused by etching) First, before explaining the embodiment, an example of shape abnormality generated during etching of a silicon film will be described. FIG17 is a diagram for explaining an example of shape abnormality generated during etching of a silicon film.

[0010] In recent years, technology for processing high-aspect-ratio holes has garnered attention in semiconductor manufacturing. One example is high-aspect-ratio contacts (HARCs). HARCs are used in DRAM (Dynamic Random Access Memory) and 3D NAND. The aspect ratio of HARCs used in DRAM is, for example, 45, while that used in 3D NAND exceeds 65.

[0011] The higher the aspect ratio of the formed hole, the more difficult it is to form a straight hole vertically. For example, as shown in Figure 17(A), the tapering phenomenon becomes more pronounced near the bottom of the hole. This phenomenon is thought to be caused, for example, by the fact that the direction of incidence of the ions in the plasma is tilted relative to the depth of the hole, making it difficult for the ions to reach the bottom of the hole. Alternatively, it is thought that the ions are trapped in the hole, obstructing their path.

[0012] Furthermore, as shown in Figure 17(B), materials removed by etching or by plasma-generated reaction products may accumulate on the substrate. If these materials accumulate near the hole opening, the hole opening may become blocked, preventing etching. Furthermore, even if the opening is not completely blocked, ions may have difficulty reaching the interior of the hole, causing distortion of the hole shape or preventing etching.

[0013] Furthermore, etching can sometimes cause the edges of the mask opening to be chipped. In this case, as shown in Figure 17(C), the incident direction of the ions becomes skewed relative to the hole, and the ions collide with the sidewalls of the hole, causing the hole to distort into a bottle-like shape, a phenomenon known as concavity.

[0014] As such, high-aspect-ratio plasma processing can be affected by the generation of radicals and ions in the plasma, as well as by the reaction products produced by the plasma processing, which can lead to variations in processing performance. Therefore, technologies are needed to individually control the generation of reactive species, radicals, and derivatives, depending on the extent of the plasma processing.

[0015] (Implementation Type) In the embodiments described below, the RF (high frequency) power used to generate the plasma is pulsed to control the parameters of the plasma process, i.e., various physical quantities. Examples of these controlled physical quantities include ion energy, ion incident angle, radical flux, ion flux, and the amount of derivatives.

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

[0017] The period during which RF power is supplied to the coil is referred to as the on-period (operating period), and the period during which RF power is not supplied to the coil is referred to as the off-period (non-operating period). The plasma source RF signal has a first state corresponding to the on-period, such as the on-state (plasma source on-state), and a second state corresponding to the off-period, such as the off-state (plasma source off-state). The plasma source RF signal is a pulse signal whose first on-period is followed by a second off-period, forming one cycle (plasma source cycle). The frequency of the plasma source RF signal can be, for example, approximately 1 kHz to approximately 5 kHz.

[0018] Furthermore, in embodiments, the plasma source RF signal can transition between two levels (e.g., a first plasma source power level and a second plasma source power level) in the first state. For example, the first state of the plasma source RF signal can include: a first level, where a predetermined RF power is supplied to the coil; and a second level, where a lower RF power than the first level is supplied to the coil. For example, the plasma source RF signal can include: a first level, where approximately 1000 watts of RF power is supplied to the coil; and a second level, where approximately 250 watts of RF power is supplied to the coil. The RF power supplied at the second level can be approximately 100 watts or approximately 150 watts. The first level and the second level can 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 ion coupling with the substrate placed above the lower electrode, thereby generating reactive species and radicals. Furthermore, the supply of RF power can be implemented in a variety of ways. For example, based on a pre-prepared program, the control unit of the plasma processing apparatus can switch the power supply paths from multiple bias RF generators, sequentially supplying bias power at different power levels in pulses.

[0020] The period during which RF power is supplied to the lower electrode is referred to as the on-period, and the period during which RF power is stopped is referred to as the off-period. The bias RF signal has a first state corresponding to the on-period, such as the on-state (bias-on state), and a second state corresponding to the off-period, such as the off-state (bias-off state). The bias RF signal is a continuous pulse signal, with one cycle (bias cycle) formed by the on-period of the first state and the subsequent off-period of the second state. The frequency of the bias RF signal can be, for example, approximately 1 kHz to approximately 5 kHz.

[0021] Furthermore, the bias RF signal of the embodiment can transition between two or more levels (e.g., a first bias power level and a second bias power level) in the first state. For example, the first state of the bias RF signal can include: a first level, where a predetermined RF power is supplied to the lower electrode; and a second level, where a lower RF power is supplied to the lower electrode. For example, the bias RF signal can include: a first level, where approximately 250 watts of RF power is supplied to the lower electrode; and a second level, where approximately 92.5 watts of RF power is supplied to the lower electrode. The first and second levels can be high and low, respectively.

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

[0023] (Configuration Example of Plasma Processing Apparatus of Embodiment Type) FIG1 is a conceptual diagram of the structure of a plasma processing apparatus according to an embodiment. FIG2 is a schematic longitudinal cross-sectional view showing an example of the structure of the plasma processing apparatus shown in FIG1 . Referring to FIG1 and FIG2 , a plasma processing apparatus 1 according to an embodiment will be described. The plasma processing apparatus 1 shown in FIG2 is a so-called inductively coupled plasma (ICP) apparatus that generates inductively coupled plasma.

[0024] 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. Plasma processing chamber 10 includes a dielectric window 10a and a sidewall 10b. Dielectric window 10a and sidewall 10b define a plasma processing space 10s within plasma processing chamber 10. Furthermore, plasma processing apparatus 1 includes a support unit 11 disposed within plasma processing space 10s, an edge ring 12, a gas inlet unit 13, and an antenna 14. Support unit 11 includes a substrate support unit 11a and an edge ring support unit 11b. Edge ring support unit 11b is disposed so as to surround the outer circumference of substrate support unit 11a. Antenna 14 is disposed above or on top of plasma processing chamber 10 (dielectric window 10a).

[0025] The substrate support portion 11a includes a substrate support area and supports the substrate on the substrate support area. In one embodiment, the substrate support portion 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 area. Although not shown in the figure, in one embodiment, the support portion 11a may include a temperature control module 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 heat transfer gas, flows through the flow path.

[0026] The edge ring 12 is arranged to surround the substrate W on the upper surface of the peripheral portion of the lower electrode. The edge ring supporting portion 11 b has an edge ring supporting region, and supports the edge ring 12 on the edge ring supporting region.

[0027] The gas inlet 13 supplies at least one processing gas from the gas supply 20 into the plasma processing space 10s. In one embodiment, the gas inlet 13 includes a central gas injection port 13a and / or sidewall gas injection ports 13b. The central gas injection port 13a is positioned above the substrate support portion 11a and is installed in a central opening formed in the dielectric window 10a. The sidewall gas injection ports 13b are installed in multiple sidewall openings formed in the sidewalls 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 supplies one or more process gases from corresponding gas sources 21 to the gas inlet via corresponding flow controllers 22. Each flow controller 22 may, for example, be a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow of one or more process gases.

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

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

[0031] Furthermore, the power supply unit 30 may include a DC power supply unit 32. In one embodiment, the DC power supply unit 32 applies 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 within the electrostatic chuck. In one embodiment, the DC signal may be pulsed. Furthermore, the DC power supply unit 32 may be provided in conjunction with the RF power supply unit 31 or in place of the bias RF generator 31b.

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

[0033] The exhaust system 40 may be connected to an exhaust port (gas outlet) 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, a control unit (corresponding to control device 50 in FIG. 2 ) processes computer-executable commands for the plasma processing apparatus 1 to perform the various processes described herein. The control unit can control various components of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit can be included in the plasma processing apparatus 1. The control unit can include, for example, a computer. The computer can include, for example, a processing unit (CPU: Central Processing Unit), a memory unit, and a communication interface. The processing unit can perform various control operations based on programs stored in the memory unit. The memory unit can include RAM (Random Access Memory), ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface can communicate with the plasma processing apparatus 1 via a communication circuit such as a LAN (Local Area Network).

[0035] (Flow of plasma treatment of implementation type) Fig. 3 is a flow chart 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 of 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 into the plasma processing chamber 10 (step S31). As shown in FIG4 , for example, substrate W includes a base layer L1, an etching target layer (Si layer) L2, and a mask MK, formed in sequence on a silicon substrate. A recess OP is previously formed in substrate W (see FIG4(A)). Furthermore, recess OP can be formed within the plasma processing apparatus 1. Next, the plasma processing apparatus 1 is controlled by a control unit to supply etching gas from the gas supply unit 20 into the plasma processing chamber 10. Furthermore, the plasma processing apparatus 1 is controlled by a control unit to supply RF power from the RF power supply unit 31 (plasma source RF generator 31a and bias RF generator 31b) to the lower electrode and antenna 14 (coil). The RF power supply unit 31 supplies RF power to the lower electrode and antenna 14 at a level corresponding to the waveform of the RF signal. The waveform of the RF signal will be described below. By supplying RF power, plasma is generated in the gas supplied to the plasma processing chamber 10, and plasma etching is performed (step S32). The plasma etching removes the bottom of the recess OP formed by the mask MK on the substrate W, gradually deepening the recess OP (see FIG4(B)). The control unit of the plasma processing apparatus 1 then determines whether a predetermined processing time has elapsed (step S33). If the predetermined processing time has elapsed, the bottom of the recess OP reaches the base layer L1, forming the shape shown in FIG4(C). 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. Otherwise, if it is determined that the processing time has elapsed (step S33, "Yes"), the control unit terminates the processing.

[0037] The plasma processing apparatus 1 of this embodiment supplies a plasma source RF signal and a bias RF signal during the plasma etching process in step S32. The plasma processing apparatus 1 controls the amount of ions and radicals in the plasma, as well as derivatives generated by the plasma etching process, by adjusting the waveforms of the plasma source RF signal and the bias RF signal. The waveforms of the plasma source RF signal and the bias RF signal are described below.

[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 plasma processing according to the embodiment.

[0039] The timing diagram 100 shown in FIG5 illustrates plasma source power (plasma source RF signal) PS and bias power (bias RF signal) PB. Plasma source power PS refers to the RF power supplied from the plasma source RF generator 31a to the antenna (coil) 14. Bias power PB refers to the RF power supplied from the bias RF generator 31b to the lower electrode in the substrate support portion 11a. The plasma source RF generator 31a generates plasma source power PS in response to, for example, a control signal supplied from a control unit. The generated plasma source power PS is supplied to the coil. The bias RF generator 31b generates bias power PB in response to, for example, a control signal supplied from a control unit. The generated bias power PS is supplied to the lower electrode.

[0040] In Figure 5, cycle 150 represents one cycle of the plasma source RF signal. Cycle 160 represents one cycle of the bias RF signal. In the following description, unless otherwise specified, cycles 1501, 1502, ... are collectively referred to as cycle 150, and cycles 1601, 1602, ... are collectively referred to as cycle 160. A cycle is the period from the rising edge of a pulse signal to the next rising edge, that is, the sum of the on and off periods. The plasma source RF signal and the bias RF signal are pulsed signals of the same frequency.

[0041] The plasma source RF signal alternates between an on state (a first state) in which RF power is supplied to the coil and an off state (a second state) in which RF power is not supplied to the coil. When the plasma source RF signal is on, plasma source power PS is supplied to the coil. When the plasma source RF signal is off, no power is supplied to the coil, i.e., RF power 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 Figure 5 , when the bias RF signal is on, bias power PB is supplied to the lower electrode. When the bias RF signal is off, no power is supplied to the lower electrode, meaning that RF power is stopped.

[0043] In Figure 5 , the rise of the bias RF signal is delayed by a period D1 relative to the rise of the plasma source RF signal. After the plasma source RF signal transitions from the on state to the off state, the bias RF signal rises while in the off state. Consequently, the timing of the start of the plasma source RF signal cycle is offset by only a period D1 from the start of the bias RF signal cycle. In the example of Figure 5 , the transition from the bias-off state (t3) in the previous bias cycle to the bias-on state PBL (t4) in the first bias cycle 1601 is delayed relative to the transition to the plasma source-on state PSH (from 0 to t1) in the first plasma source cycle 1501 corresponding to the first bias cycle 1601. Furthermore, as shown at t3 in Figure 5 , the plasma source off period partially overlaps with the bias off period. Furthermore, as shown in t6 of FIG. 5 , the bias-on period of the first bias cycle 1601 partially overlaps with the plasma source-on period of the second plasma source cycle 1502 .

[0044] Furthermore, the lengths of the on-period and off-period of the plasma source RF signal differ from the lengths of the on-period and off-period of the bias RF signal. In the example of FIG5 , the duty ratio of the plasma source RF signal (the ratio of the on-period to the length of one cycle) is approximately 40%. Furthermore, the duty ratio of the bias RF signal is approximately 60%. However, the duty ratios of the plasma source RF signal and the bias RF signal are not limited to the aforementioned values. Furthermore, the plasma source RF signal and the bias RF signal may have the same duty ratio.

[0045] In this way, the plasma source RF signal and the bias RF signal undergo state transitions respectively. The timing of the state transition of the plasma source RF signal and the power levels of the transition source and the transition destination are different from those of the bias RF signal.

[0046] There is a period TOFF during which neither the plasma source RF signal nor the bias RF signal is supplied, and a period TON during which both the plasma source RF signal and the bias RF signal are supplied. The supply patterns of the plasma source power PS and the bias power PB transition through the following five phases.

[0047] (1) Phase 1 (ST1 in Figure 5): The first phase is defined by the parameter set {PS1, PB1, t1}. PS1 is the value of the plasma source power PS supplied during the first phase. PB1 is the value of the bias power PB supplied during the first phase. t1 represents the duration of the first phase. The following relationship holds true. PS1>0 PB1>0 t1>0

[0048] In the first phase, plasma source power PS at a high power level PSH (first plasma source power level) is supplied to the coil, and bias power PB at a high power level PBH (second bias power level) is supplied to the lower electrode. During period t1 of the first phase, RF power is supplied to both the upper and lower portions of the plasma processing apparatus 1, generating plasma and producing ions and radicals in the plasma. During etching, etching proceeds during period t1.

[0049] (2) Phase 2 (ST2 in Figure 5): The second phase is defined by the parameter set {PS2, PB2, t2}. PS2 is the value of the plasma source power PS supplied during the second phase. PB2 is the value of the bias power PB supplied during the second phase. t2 represents the duration of the second phase. The following relationship holds true. PS1>PS2>0 PB2=0 t2>0

[0050] In the second phase, plasma source power PS at a low power level PSL (second plasma source power level) is supplied to the coil, and the supply of bias power PB is stopped. The second phase is, for example, period t2 in Figure 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, no force is generated to attract ions toward the lower electrode. Furthermore, the amount of ions and radicals generated is reduced.

[0051] (3) Phase 3 (ST3 in Figure 5): The third phase is defined by the parameter set {PS3, PB3, t3}. PS3 is the value of the plasma source power PS supplied during the third phase. PB3 is the value of the bias power PB supplied during the third phase. t3 represents the duration of the third phase. The following relationship holds true. PS3=PB3=0 t3>0

[0052] In the third phase, the supply of both plasma source power PS and bias power PB is stopped. The third phase is, for example, period t3 in Figure 5 . During period t3, when plasma generation within the plasma processing apparatus 1 ceases, the plasma processing space 10s is evacuated by the exhaust system 40 . At this time, the derivatives (byproducts) generated by etching and retained at the bottom of the recess ( OP in Figure 4 ) are exhausted. The amount of ions and radicals within the plasma processing space 10s is also reduced.

[0053] (4) Phase 4 (ST4 in Figure 5): The fourth phase is defined by the parameter set {PS4, PB4, t4}. PS4 is the value of the plasma source power PS supplied during the fourth phase. PB4 is the value of the bias power PB supplied during the fourth phase. t4 represents the duration of the fourth phase. The following relationship holds true. PS4=0 PB1>PB4>0 t4>0

[0054] During the fourth phase, while the supply of plasma source power PS is stopped, bias power PB at a low power level PBL (first bias power level) is supplied. During period t4 of the fourth phase, plasma is not generated because plasma source power PS is not supplied. However, ions generated during the first and second phases remain within the plasma processing space for 10 seconds. Consequently, the supply of bias power PB draws ions into the bottom of the recess (OP, Figure 4). Furthermore, the closer the ion incident angle is to vertical, the smoother the vertical etching of the sidewalls of recess OP.

[0055] (5) Phase 5 (ST5 in Figure 5): The fifth phase is defined by the parameter set {PS5, PB5, t5}. PS5 is the value of the plasma source power PS supplied during the fifth phase. PB5 is the value of the bias power PB supplied during the fifth phase. t5 represents the duration of the fifth phase. The following relationship holds true. PS5=0 PB1=PB5>PB4>0 t5>0

[0056] During the fifth phase, while the supply of plasma source power PS is stopped, the power level of bias power PB increases (transitions) from a low power level PBL to a high power level PBH. Therefore, as a preparatory step for the first phase, the ion energy within the plasma processing space increases during the fifth phase for 10 seconds. The decrease in the amount of radicals and their derivatives during the third phase continues.

[0057] After the fifth phase, the process returns to the first phase, where high-power plasma source power PS and high-power bias power PB are applied simultaneously. This cycle repeats. In the fifth phase, while ion energy is generated by applying bias power PB, the first phase begins, applying plasma source power PS to generate ions and radicals. This accelerates etching in the first phase and efficiently draws ions into the bottom of recess OP. Furthermore, in the third phase, etching is further accelerated by discharging derivatives.

[0058] In this way, by using the plasma source RF signal and bias RF signal having the pulse waveform shown in Figure 5, the states of ions, radicals, and derivatives within the plasma processing space 10s can be suppressed while simultaneously achieving vertical etching. This can suppress shape anomalies caused by etching and improve plasma etching processing performance.

[0059] In the example of Figure 5 , the plasma source power PS takes the value PSH during the on state during period t1 and the value PSL during the on state during the following period t2. Furthermore, the bias power PB takes the value PBL during period t4 and transitions to the value PBH during the subsequent period t5. In this way, by controlling various physical quantities of the plasma according to the plasma processing method of the embodiment, the on state of the plasma source RF signal can be controlled at two levels (including the off state, for a total of three levels). Furthermore, in the plasma processing method of the embodiment, the on state of the bias RF signal can be controlled at two levels (including the off state, for a total of three levels). In this way, by gradually varying the RF power values ​​applied to the coil and the lower electrode, more detailed plasma processing parameter adjustment is possible.

[0060] In the example of FIG5 , the following relationship holds true. 0 <PSL<PSH 0 <PBL<PBH Frequency of plasma source RF signal and bias RF signal: 0.1kHz~5kHz Plasma source RF signal duty cycle: about 40% Bias RF signal duty cycle: about 60% The length of the PSH period: the length of the PSL period = 1:3 The length of the PBH period: the length of the PBL period = 1:2 t1:t2:t3:t4:t5=1:3:1:4:1 However, this embodiment is not only applicable to the case where the above relationship is established, but also applicable to other relationships. Regarding other relationships, as modified examples, they are described below.

[0061] 6 to 9 are diagrams for explaining how the waveform of an RF signal corresponds to changes in physical quantities within the plasma processing chamber 10. Referring to FIG6 to FIG9 , the changes in physical quantities corresponding to the waveform of an RF signal are explained.

[0062] Waveform Example 1 in Figure 6 includes a "first phase," in which both plasma source power and bias power are supplied simultaneously; a "second phase," in which only plasma 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 aforementioned embodiments in that it lacks a "third phase," in which no RF power is supplied, and a "fifth phase," in which the bias power level is varied before the plasma source RF signal rises. In Waveform Example 1, in the first phase, the ion flux, radical flux, and ion energy all increase, while the amount of derivatives increases. Subsequently, in the second phase, all these quantities gradually decrease. By ceasing the bias power supply, the ion energy reaches approximately zero. In the fourth phase, the supply of bias power increases the ion energy compared to the first phase. Furthermore, the ion flux, radical flux, and amount of derivatives do not change significantly compared to the second phase.

[0063] Waveform Example 2 in Figure 7 is substantially the same as Waveform Example 1 in Figure 6 . However, the bias power value (PBM) in Phase 4 is increased compared to the bias power value (PBL) in Waveform Example 1. In the example in Figure 7 , the ion flux, radical flux, and derivative amount are substantially the same as in Waveform Example 1 in Figure 6 . However, the ion energy in Phase 4 is increased compared to Waveform Example 1 (C1 in Figure 7 ). Furthermore, in Figure 7 (C), the same dashed line as in Figure 6 (C) indicates the change in ion energy in the case of Figure 7 (A), with only the portion that differs from Figure 6 (C) being indicated by the thick dashed line C1.

[0064] Compared to Waveform Example 1 in Figure 6 , Waveform Example 3 in Figure 8 shows a longer first phase and a correspondingly shorter second phase. In the example in Figure 8 , the ion flux and radical flux increase from the first to the second phase compared to the example in Figure 6 (C2 and C3 in Figure 8 ). Furthermore, the ion energy and derivative amounts do not change significantly. The thick dashed lines C2 and C3 are identical to those in C1 above, and only the portions shown in Figure 6 differ.

[0065] Waveform Example 4 in Figure 9 differs from Waveform Example 1 in Figure 6 in the inclusion of a fifth phase. The power level in the fifth phase shifts from the power level PBL in the fourth phase to PBH. In the example in Figure 9 , the ion flux, radical flux, and derivative amounts are substantially the same as in Waveform Example 1 in Figure 6 . Ion energy increases in the fifth phase (C4 in Figure 9 ) as the bias power PB is switched. The thick dashed line C4 in Figure 9 only indicates the portion that differs from (D) in Figure 6 .

[0066] Furthermore, when etching is performed using the RF power waveforms shown in Figures 6 to 9, the variation in the dimension (critical dimension) from the top to the bottom of the recess is greater in Waveform Examples 1 and 3 than in Waveform Example 2. In other words, by supplying a slightly higher level of bias power, as in the fourth phase of Waveform Example 2, holes of uniform size can be formed in the vertical direction during deep hole etching. Furthermore, by varying the ratio of the lengths of the first phase to the second phase, as in Waveform Example 3, mask consumption is reduced, enabling selective etching of the target film. Thus, it can be seen that the state of ions or radicals, particularly near the target substrate, changes within the plasma processing space 10s, depending on the RF power waveform, affecting the performance of the plasma processing. Therefore, by adjusting the waveform of the RF signal, the performance of the plasma processing, and therefore the shape of the pattern formed by the plasma processing, can be controlled.

[0067] Furthermore, waveform examples 1-4 in Figures 6-9 do not include the third phase of this embodiment, that is, the phase in which no RF power is supplied to the coil or the lower electrode. By introducing the third phase in which no RF power is supplied, the amount of derivatives within the plasma processing space 10s can be further reduced, thereby improving vertical etching accuracy.

[0068] In addition, this embodiment is not limited to the waveform of FIG5, and the same effect can be obtained by using modified examples. The following describes modified examples 1 to 5 with reference to FIG10 to FIG14.

[0069] (Variation 1) FIG10 illustrates an example waveform of an RF signal used for supplying RF power during plasma processing in Modification 1. The timing diagram 200 shown in FIG10 illustrates plasma source power PS and bias power PB. First, at the start of period t1, plasma source power PSH and bias power PBH are applied. Throughout period t1, plasma source power PSH and bias power PBH are applied in an overlapping manner at a constant level. Next, at period t3, both the supply of plasma source power PS and bias power PB are stopped (period TOFF). Next, at period t4, the supply of bias power PBH is resumed. Then, at the timing of the next cycle 1502, the supply of plasma source power PSH is resumed, and the plasma source power PSH and bias power PBH are applied in an overlapping manner (period TON).

[0070] Unlike the waveform example in Figure 5 , the timing diagram 200 in Figure 10 does not have a second phase, that is, a phase in which the plasma source power PS continues to be supplied to the coil while the bias power PB is stopped. Furthermore, the timing diagram 200 in Figure 10 does not have a fifth phase, that is, a phase in which the level of the bias power PB changes before the plasma source power PS is supplied. Therefore, Modification 1 is applicable in situations where pattern formation is suitable for starting the emission of derivatives (the third phase) without adjusting the amount of ions or radicals. Modification 1 is also applicable in situations where it is not necessary to generate ion energy before plasma generation.

[0071] (Variation 2) FIG11 illustrates an example waveform of an RF signal used for supplying RF power during plasma processing in Modification 2. In the timing diagram 210 shown in FIG11 , plasma source power PSH and bias power PBH are first applied during period t1. During the next period t2, the level of plasma source power PS changes from PSH to PSM. Furthermore, at the start of period t2, the supply of bias power PBH is stopped. Next, during period t3, the supply of plasma source power PSM is stopped. Therefore, during period t3, neither plasma source power PS nor bias power PB is supplied (period TOFF). Then, during period t4, the supply of bias power PBM begins. During period t4, bias power PB is supplied at level PBM. Then, during period t5, the level of bias power PB changes from PBM to PBH. Then, while the bias power PBH is being supplied, when the next cycle 1502 comes, the plasma source power PSH is supplied, and the plasma source power PSH and the bias power PBH are supplied in an overlapping manner (period TON).

[0072] Compared to the waveform example in FIG5 , Modification 2 differs in that the plasma source power PS level is set to PSH and PSM. Furthermore, the plasma source power PS level is set in the order of PSH, PSM, and PSL, from a high level to a low level. Furthermore, compared to the waveform example in FIG5 , Modification 2 differs in that the bias power PB level is set to PBH and PBM. Furthermore, the bias power PB level is set in the order of PBH, PBM, and PBL, from a high level to a low level. In Modification 2, the on-states of the plasma source power PS and the bias power PB are set to two levels. However, the lower of the two levels is set to a higher level than in the example in FIG5 .

[0073] For example, before and after the third phase of the derivative discharge, if one wishes to maintain the electron density Ne, radical density Nr, electron temperature Te, ion energy εi, etc. at a high level, the levels of the multiple on-states of the plasma source power PS and the bias power PB can be set higher as in Modification Example 2.

[0074] In Modification 2, as in the waveform example of FIG5 , the rise of the bias RF signal is delayed by a period D1 relative to the rise of the plasma source RF signal. Furthermore, there is a period TOFF during which neither the plasma source power PS nor the bias power PB is supplied. Furthermore, there is a period TON during which both the plasma source power PS and the bias power PB are supplied. Period TON is the period from the rise of the plasma source RF signal to the fall of the bias RF signal.

[0075] (Variation 3) FIG12 illustrates an example waveform of an RF signal used for supplying RF power during plasma processing according to Modification 3. In the timing diagram 220 shown in FIG12 , plasma source power PSH and bias power PBM are first supplied during period t1. Next, during period t2, the level of plasma source power PS changes from PSH to PSM. Furthermore, during period t2, the supply of bias power PBM is stopped. Next, during period t3, the supply of plasma source power PSM is stopped. During period t3, neither plasma source power PS nor bias power PB is supplied (TOFF). Then, during period t4, the supply of bias power PBH is started. During period t4, bias power PB is supplied at level PBH. Finally, during period t5, the level of bias power PB changes from PBH to PBM. Then, while the bias power PBM is being supplied, when the cycle 1502 starts, the plasma source power PSH is supplied, and the plasma source power PSH and the bias power PBM are supplied in an overlapping manner (period TON).

[0076] Modification 3 is substantially similar to Modification 2 in FIG11 . However, the order in which the bias power PB level transitions in Modification 3 differs from that in Modification 2. In Modification 2, the bias power PB level during period t1 is PBH, during period t4 is PBM, and during period t5 is PBH. In contrast, in Modification 3, the bias power PB level during period t1 is PBM, during period t4 is PBH, and during period t5 is PBM. In Modification 2, the bias power PB level changes from the first phase to the fifth phase in the order of high, off, low, and high. In contrast, in Modification 3, the bias power PB level changes from the first phase to the fifth phase in the order of low, off, high, and low.

[0077] Then, in the case of plasma processing suitable for increasing the ion energy in the third phase and sucking many ions toward the bottom of the recess OP, the waveform of the modified example 3 is suitable for use.

[0078] (Variation 4) FIG13 illustrates an example waveform of an RF signal used for supplying RF power during plasma processing according to Modification 4. In the timing diagram 230 shown in FIG13 , plasma source power PSM and bias power PBH are first applied during period t1. Next, during period t2, the level of plasma source power PS changes from PSM to PSH. Furthermore, at period t2, the supply of bias power PBH is stopped. Next, during period t3, the supply of plasma source power PSH is stopped. During period t3, neither plasma source power PS nor bias power PB is supplied (TOFF). Then, during period t4, the supply of bias power PBM begins. During period t4, bias power PB is supplied at level PBM. Then, at period t5, the level of bias power PB changes from PBM to PBH. Then, when the supply of the bias power PBH continues for a period of time 1502, the plasma source power PSM is supplied, and the plasma source power PSM and the bias power PBH are supplied in an overlapping manner (period TON).

[0079] Modification 4 is substantially the same as Modification 2 in FIG11 . However, the order in which the plasma source power PS level transitions in Modification 4 differs from that in Modification 2. In Modification 2, the plasma source power PS level during period t1 is PSH, and during period t2 is PSM. In contrast, in Modification 4, the plasma source power PS level during period t1 is PSM, and during period t2 is PSH. In Modification 2, the plasma source power PS level changes from the first phase to the third phase in the order of high, low, and off, and remains unchanged from the third phase to the fourth phase. In contrast, in Modification 4, the plasma source power PS level changes from the first phase to the third phase in the order of low, high, and off, and remains unchanged from the third phase to the fourth phase.

[0080] Modification 4 is suitable for, for example, a process that prefers a gradual increase in the amount of ions and radicals rather than a rapid increase in the amount of ions and radicals in the first phase.

[0081] (Variant 5) FIG14 illustrates an example waveform of an RF signal used for supplying RF power during plasma processing according to Modification 5. In the timing diagram 240 shown in FIG14 , plasma source power PSM and bias power PBM are first applied during period t1. Next, during period t2, the level of plasma source power PS changes from PSM to PSH. Furthermore, during period t2, the supply of bias power PBM is stopped. Next, during period t3, the supply of plasma source power PSH is stopped. During period t3, neither plasma source power PS nor bias power PB is supplied (TOFF). Then, during period t4, the supply of bias power PBH begins. During period t4, bias power PB is supplied at level PBH. Then, during period t5, the level of bias power PB changes from PBH to PBM. Then, when the supply of the bias power PBM continues for a period 1502, the plasma source power PSM is supplied, and the plasma source power PSM and the bias power PBM are supplied in an overlapping manner (TON).

[0082] Modification 5 combines the bias power PB of Modification 3 in Figure 12 with the plasma source power PS of Modification 4 in Figure 13 . The bias power PB of Modification 3 changes from the first phase to the fifth phase in the order of low level (first phase), off state (second and third phases), high level (fourth phase), and low level (fifth phase). Furthermore, the plasma source power PS of Modification 4 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, in the waveform of Modification 5, {PS, PB} change from the first phase to the fifth phase in the order of {PSM, PBM} {PSH, PBOFF} {PSOFF, PBOFF} {PSOFF, PBH} {PSOFF, PBM}. Furthermore, when a waveform contains only two on-state levels, for convenience, one level is referred to as the high level and the other as the low level, rather than the mid-level. Furthermore, the off-state of the plasma source power PS is displayed as PSOFF, and the off-state of the bias power PB is displayed as PBOFF.

[0083] Modification 5 is suitable for, for example, a process in which etching is preferably performed after first increasing and then decreasing the ion energy in the fourth phase.

[0084] (RF power supply process) Fig. 15 is a flow chart showing an example of the flow of RF power supply in plasma processing according to the embodiment. The flow 1500 shown in Fig. 15 is executed, for example, in step S32 of Fig. 3 .

[0085] First, under the control of the control unit, the RF power supply unit 31 performs the first phase of RF power supply (step S1510). The first phase of RF power supply is specified by the first set of processing parameters {PS1, PB1, t1}. Here, PS1>0, PB1>0, and t1>0.

[0086] Next, under the control of the control unit, the RF power supply unit 31 performs the second phase of RF power supply (step S1520). The second phase of RF power supply is specified by the second set of processing parameters {PS2, PB2, t2}, where PS2>0, PB2=0, and t2≧0.

[0087] Next, under the control of the control unit, the RF power supply unit 31 performs RF power supply in the third phase (step S1530). The RF power supply in the third phase is specified by the third set of processing parameters {PS3, PB3, t3}, where PS3 = 0, PB3 = 0, and t3 > 0.

[0088] Next, under the control of the control unit, the RF power supply unit 31 performs RF power supply in the fourth phase (step S1540). The RF power supply in the fourth phase is specified by the fourth set of processing parameters {PS4, PB4, t4}, where PS4 = 0, PB4 > 0, and t4 > 0.

[0089] Next, under the control of the control unit, the RF power supply unit 31 performs RF power supply in the fifth phase (step S1550). The RF power supply in the fifth phase is specified by the fifth set of processing parameters {PS5, PB5, t5}, where PS5 = 0, PB5 > 0, and t5 ≥ 0.

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

[0091] Fig. 16 is a flow chart showing another example of the process of supplying RF power to the plasma process according to the embodiment. The process 1600 shown in Fig. 16 is executed, for example, in step S32 of Fig. 3 .

[0092] First, under the control of the control unit, the RF power supply unit 31 supplies plasma source power PS to the antenna (coil) 14 and bias power PB to the lower electrode. This generates plasma within 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 stops supplying bias power PB to the lower electrode. Furthermore, the RF power supply unit 31 changes the value of the plasma source power PS supplied to the antenna (coil) 14. For example, the RF power supply unit 31 decreases or increases the plasma source power PS. In this way, the RF power supply unit 31 adjusts the number of ions and radicals contained in the plasma within the plasma processing space 10s (step S1620).

[0094] Next, under the control of the control unit, the RF power supply unit 31 stops supplying the plasma source power PS to the coil while the bias power PB is stopped from being supplied to the lower electrode. The plasma processing space 10s is then exhausted by the exhaust system 40, thereby reducing the amount of derivatives within the plasma processing space 10s (step S1630).

[0095] Next, under the control of the control unit, the RF power supply unit 31 supplies bias power PB toward the lower electrode. The supply of plasma source power PS remains stopped. The bias power PB generates a suction force toward the lower electrode (step S1640).

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

[0097] Furthermore, some of the above-mentioned embodiments and modifications may be appropriately changed. The following describes the modifications considered.

[0098] (Other embodiments) The plasma source power PS can be alternating current (AC) power. Alternatively, the plasma source power PS can be high-frequency (RF) power or very high-frequency (VHF) power. For example, the plasma source power PS can be RF power in the range of approximately 60 MHz to approximately 200 MHz. Alternatively, the plasma source power PS can be RF power in the range of approximately 25 MHz to approximately 60 MHz. For example, the plasma source power PS can be 27 MHz. In this embodiment, the plasma source power PS generates inductively coupled plasma (ICP). For example, the plasma source power PS is coupled to a helical antenna to generate plasma.

[0099] The bias power PB can be alternating current (AC) power. Alternatively, the bias power PB can be direct current (DC) pulse power. The bias power PB can be any of RF (radio frequency) power, HF (high frequency) power, and MF (medium frequency) power. For example, the bias power PB can have a frequency in the range of approximately 200 kHz to approximately 600 kHz. For example, the bias power PB can have a frequency of 400 kHz. Furthermore, the bias power PB can have a frequency in the range of approximately 600 kHz to approximately 13 MHz.

[0100] The plasma source power PS and bias power PB can be applied as a single pulse or as a continuous pulse in each cycle. For example, in the first phase, the plasma source power PS1 applied during period t1 can be a single pulse or a continuous pulse. Similarly, the bias power PB2 applied during period t2 can be a single pulse or a continuous pulse.

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

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

[0103] Furthermore, the duty cycle in the on-state when the bias RF signal is at a high level can be set within a range of approximately 5% to approximately 50%. Furthermore, the duty cycle in the on-state when the bias RF signal is at a low level can be set within a range of 0% to approximately 45%. Furthermore, the duty cycle in the off-state when the bias RF signal is at an off level can be set within a range of approximately 5% to approximately 90%.

[0104] Furthermore, the duration of the period during which the plasma source RF signal and the bias RF signal are simultaneously turned off can be set within a duty cycle range of approximately 5% to approximately 90%. For example, this period can be set within a range of approximately 0 microseconds to approximately 500 microseconds, more preferably within a range of approximately 10 microseconds to approximately 50 milliseconds. Furthermore, during this period, the duty ratios of the plasma source RF signal and the bias RF signal can be set within a range of approximately 10% to approximately 50%.

[0105] Gas is supplied to the plasma processing chamber 10 at a flow rate selected to match a predetermined plasma process. During a cycle comprising a first phase, a second phase, a third phase, a fourth phase, and a fifth phase, the gas is supplied to the plasma processing chamber 10 at substantially the same flow rate. The supplied gas may include, for example, hydrogen bromide (HBr). Alternatively, the supplied gas may include, for example, a noble gas such as helium (He) or argon (Ar). Alternatively, the supplied gas may include, for example, oxygen (O2), carbon tetrafluoride (CF4), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), chlorine (Cl2), or carbon tetrachloride (CCl4).

[0106] Derivatives generated during plasma processing in this embodiment can be compounds containing one or more elements contained in the gas within plasma processing chamber 10 and the substrate composition. For example, when using a silicon substrate and HBr gas, derivatives containing SiBrx can be formed. Derivatives can also form silicon-containing residues such as silicon fluoride (SiFx) and silicon chloride (SiClx), or (in the case of processing using photoresist films, organic films, or precursors) silicon-containing residues such as fluorocarbons (CFx) and hydrofluorocarbons (CHxFy).

[0107] (Effect of implementation type) As described above, the plasma processing apparatus of the embodiment includes: a plasma processing chamber; a substrate support; a plasma source RF generator; and a bias RF generator. The substrate support is disposed within the plasma processing chamber. The plasma source RF generator is coupled to the plasma processing chamber and generates a pulsed plasma source RF signal comprising a plurality of plasma source cycles. Each plasma source cycle includes a plasma source operating state between plasma source operating periods and a plasma source non-operating state between plasma source non-operating periods following the plasma source operating periods. The bias RF generator is coupled to the substrate support and generates a pulsed bias RF signal. The pulsed bias RF signal includes a plurality of bias cycles having the same pulse frequency as the plurality of plasma source cycles. Each bias cycle includes a bias operating state between bias operating periods and a bias non-operating state between bias non-operating periods following the bias operating periods. The timing of transition to the bias operating state in each bias cycle is delayed relative to the timing of transition to the plasma source operating state in the corresponding plasma source cycle. The plasma source off period overlaps with the bias non-operation period. The bias operation period of each bias cycle overlaps with the plasma source operation period of the subsequent plasma source cycle. In this way, the plasma processing device supplies the RF signal with the cycles of the pulsed plasma source RF signal and the pulsed bias signal staggered. Furthermore, the plasma processing device continuously supplies the RF signal with the bias operation period spanning two cycles of the pulsed plasma source RF signal. Therefore, the plasma processing device can finely control the ion energy generated during plasma etching, thereby improving plasma etching performance. Furthermore, by staggering the plasma source operation period and the bias operation period, the plasma processing device can set the power level supplied at the rising edge of the pulsed plasma source RF signal (at the beginning of the cycle) to a higher level. Therefore, the plasma processing device can achieve efficient plasma etching.

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

[0109] As described above, in the plasma processing apparatus of the embodiment, the plasma source operating state may include: a first plasma source power level; and a second plasma source power level subsequent to the first plasma source power level. The bias operating state may include: 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 the plasma source non-operation period of each plasma source cycle.

[0110] As described above, in the plasma processing apparatus of the embodiment, the bias RF signal can be shifted from the first bias power level to the second bias power level during the plasma source non-operation period of each plasma source cycle.

[0111] As described above, in the plasma processing apparatus of the embodiment, the transition from the first plasma source power level to the second plasma source power level in each plasma source cycle can be substantially synchronized with the transition from the bias operating state to the bias non-operating state in each bias cycle.

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

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

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

[0116] Furthermore, the plasma processing method of the above-described 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 positioned 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 positioned 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, the steps of supplying the first RF power to the antenna and supplying the second RF power to the substrate support. Furthermore, during a second period following the first period, the plasma processing method may include the steps of supplying the first RF power to the antenna and stopping the supply of the second RF power to the substrate support. Furthermore, during a third period following the second period, the plasma processing method may include the steps of stopping the supply of the first RF power to the antenna and stopping the supply of the second RF power to the substrate support. Furthermore, the plasma processing method may include a step of supplying the second RF power to the substrate support portion in a fourth period after the third period without supplying RF power to the antenna. The plasma processing method may then repeat each step.

[0117] The embodiments disclosed herein should be considered in all respects as illustrative and non-restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the above embodiments illustrate a plasma processing method using an inductively coupled plasma device, but the disclosed technology is not limited thereto. The technology of the present invention may also be applied to plasma processing methods using other plasma devices. For example, a capacitively coupled plasma (CCP) device may be used instead of an inductively coupled plasma device. In this case, the capacitively coupled plasma device includes two opposing electrodes disposed within the plasma processing chamber. In one embodiment, one electrode is disposed within the substrate support portion, and the other electrode is disposed above the substrate support portion. In this case, one electrode functions as a lower electrode, and the other electrode functions as an upper electrode. The plasma 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 plasma source RF generator 31a is coupled to the upper electrode, and the bias RF generator 31b is coupled to the lower electrode. Alternatively, the plasma source RF generator 31a and the bias RF generator 31b may be coupled to the lower electrode.

[0118] 1: Plasma processing device 10: Plasma processing chamber 10a: Dielectric window 10b: Sidewall 10s: Plasma processing space 11: Support Department 11a: substrate support part 11b: Edge ring support 12: Edge Ring 13: Gas inlet 13a: Central gas injection unit 13b: Side wall gas injection part 14: Antenna 20: Gas supply unit 21: Gas source 22: Flow controller 30: Power supply unit 31: RF power supply unit 31a: Plasma source RF generating unit 31b: Bias RF generating unit 32: DC power supply unit 40: Exhaust system S31~S33,S1510,S1520,S1530,S1540,S1550,S1610,S1620,S1630,S1640: Steps W: substrate

Claims

1. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; and a plasma source RF generation unit coupled to the plasma processing chamber and generating a plasma source RF signal for generating plasma within the plasma processing chamber, wherein the plasma source RF signal has a zero power level in a first period of each cycle, a zero power level in a second period following the first period of each cycle, a first plasma source power level greater than zero power level in a third period following the second period of each cycle, and a first plasma source power level greater than zero power level and different from the first power level in a fourth period following the third period of each cycle. The second plasma source power level of the plasma source power level has a zero power level in the fifth period of the fourth period that follows each cycle; and the bias RF generation unit is coupled to the substrate support unit and generates a bias RF signal, wherein the bias RF signal has a first bias power level that is greater than the zero power level in the first period, a second bias power level that is greater than the zero power level and different from the first bias power level in the second and third periods, and a zero power level in the fourth and fifth periods.

2. The plasma treatment apparatus as claimed in claim 1, wherein, The power level of the first plasma source is greater than that of the second plasma source.

3. The plasma treatment apparatus as claimed in claim 1 or 2, wherein, The first bias power level is smaller than the second bias power level.

4. The plasma treatment apparatus as claimed in claim 1 or 2, wherein, The first bias voltage level is greater than the second bias voltage level.

5. The plasma treatment apparatus as claimed in claim 1, wherein, The power level of the first plasma source is lower than that of the second plasma source.

6. The plasma treatment apparatus as claimed in claim 5, wherein, The first bias power level is smaller than the second bias power level.

7. The plasma treatment apparatus as claimed in claim 5, wherein, The first bias voltage level is greater than the second bias voltage level.

8. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; a plasma source RF generation unit coupled to the plasma processing chamber and generating a plasma source RF signal for generating plasma within the plasma processing chamber, wherein the plasma source RF signal has a zero power level in a first period of each cycle, a first plasma source power level greater than zero power level in a second period following the first period of each cycle, and a zero power level in a third period following the second period of each cycle; and a bias RF generation unit coupled to the substrate support and generating a bias RF signal, wherein the bias RF signal has a first bias power level greater than zero power level in the first and second periods, and a zero power level in the third period.

9. The plasma treatment apparatus as claimed in claim 8, wherein, The substrate support includes a lower electrode that is electrically connected to the bias RF generation section.

10. The plasma processing apparatus of claim 9 further comprises: an antenna disposed above the plasma processing chamber and electrically connected to the plasma source RF generating unit.

11. The plasma processing apparatus of claim 9 further comprises: an upper electrode disposed above the substrate support and electrically connected to the plasma source RF generating unit.

12. A power supply system for use in a plasma processing apparatus, comprising: A plasma source RF generation unit generates a plasma source RF signal, wherein the plasma source RF signal has a zero power level in the first period of each cycle, a zero power level in the second period following the first period of each cycle, a first plasma source power level greater than zero power level in the third period following the second period of each cycle, a second plasma source power level greater than zero power level and different from the first plasma source power level in the fourth period following the third period of each cycle, and a zero power level in the fifth period following the fourth period of each cycle; and a bias RF generation unit generates a bias RF signal, wherein the bias RF signal has a first bias power level greater than zero power level in the first period, a second bias power level greater than zero power level and different from the first bias power level in the second and third periods, and a zero power level in the fourth and fifth periods.

13. The power system as described in request item 12, wherein, The power level of the first plasma source is greater than that of the second plasma source.

14. The power system as requested in item 12 or 13, wherein, The first bias power level is smaller than the second bias power level.

15. The power system as requested in item 12 or 13, wherein, The first bias voltage level is greater than the second bias voltage level.

16. The power system as described in request item 12, wherein, The power level of the first plasma source is lower than that of the second plasma source.

17. The power system as described in request item 16, wherein, The first bias power level is smaller than the second bias power level.

18. The power system as described in request item 16, wherein, The first bias voltage level is greater than the second bias voltage level.

19. A power supply system for use in a plasma processing apparatus, comprising: a plasma source RF generation unit that generates a plasma source RF signal, wherein the plasma source RF signal has a zero power level in a first period of each cycle, a first plasma source power level greater than the zero power level in a second period following the first period of each cycle, and a zero power level in a third period following the second period of each cycle; and a bias RF generation unit that generates a bias RF signal, wherein the bias RF signal has a first bias power level greater than the zero power level in the first and second periods, and a zero power level in the third period.

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