Plasma processing method and plasma processing apparatus

Abstract

The present application provides a kind of plasma processing method and plasma processing device, can improve the processing performance of plasma. Plasma processing device includes plasma processing chamber, substrate support part, source RF generation part, bias RF generation part. Substrate support part is arranged in plasma processing chamber. Source RF generation part is combined with plasma processing chamber, generates the pulse source RF signal including multiple source cycles. Each source cycle has source running state and source non-running state. Bias RF generation part is combined with substrate support part, generates pulse bias RF signal. Pulse bias RF signal has multiple bias cycles with the same pulse frequency as multiple source cycles, each bias cycle has bias running state and bias non-running state. The transition moment to bias running state in each bias cycle is delayed relative to the transition moment to source running state in the corresponding source cycle.

Description

Technical Field

[0001] This invention relates to plasma processing methods and plasma processing apparatus. Background Technology

[0002] Patent Document 1 discloses a technique for pulsed RF (Radio Frequency) signals in a device using inductively coupled plasma (also known as Inductively Coupled Plasma: ICP, Transformer Coupled Plasma: TCP). For example, Patent Document 1 discloses a technique for synchronizing a source RF signal supplied to a coil and a bias RF signal supplied to a chuck in an inverse pulse sequence.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: U.S. Patent Application Publication No. 2017 / 0040174 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] This invention provides a technique that can improve the processing performance of plasma.

[0008] Technical solutions for solving technical problems

[0009] One aspect of the plasma processing apparatus of the present invention includes a plasma processing chamber, a substrate support, a source RF generation unit, and a bias RF generation unit. The substrate support is disposed within the plasma processing chamber. The source RF generation unit is coupled to the plasma processing chamber and generates a pulsed source RF signal comprising multiple source cycles. Each source cycle has a source operating state during a source operating period and a source non-operating state during a source non-operating period following the source operating period. 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 having the same pulse frequency as the multiple source cycles. Each bias cycle has a bias operating state during a bias operating period and a bias non-operating state during a bias non-operating period following the bias operating period. The transition time to the bias operating state in each bias cycle is delayed relative to the transition time to the source operating state in the corresponding source cycle. The source non-operating period overlaps with the bias non-operating period. The bias operating period in each bias cycle overlaps with the source operating period in the next source cycle.

[0010] Invention Effects

[0011] According to the present invention, the plasma processing performance can be improved. Attached Figure Description

[0012] Figure 1 This is a conceptual diagram of the configuration of the plasma processing apparatus according to the embodiment.

[0013] Figure 2 It means Figure 1 A schematic longitudinal cross-sectional view of an example of the configuration of a plasma processing device.

[0014] Figure 3 This is a flowchart illustrating an example of a plasma processing procedure in an implementation method.

[0015] Figure 4 This is a diagram illustrating an example of a substrate processed by the plasma processing described in this embodiment.

[0016] Figure 5 This is a diagram illustrating an example of the waveform of the RF signal used for high-frequency (RF) power supply in the plasma processing of the embodiment.

[0017] Figure 6 This is a diagram used to illustrate the changes in physical quantities within the plasma processing chamber corresponding to the waveform of the RF signal in Example 1.

[0018] Figure 7 This is a diagram used to illustrate the changes in physical quantities within the plasma processing chamber corresponding to the waveform of the RF signal in Example 2.

[0019] Figure 8 This is a graph used to illustrate the changes in physical quantities within the plasma processing chamber corresponding to the waveform of the RF signal in Example 3.

[0020] Figure 9 This is a graph used to illustrate the changes in physical quantities within the plasma processing chamber corresponding to the waveform of the RF signal in Example 4.

[0021] Figure 10 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 1.

[0022] Figure 11 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 2.

[0023] Figure 12 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 3.

[0024] Figure 13 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 4.

[0025] Figure 14 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 5.

[0026] Figure 15 This is a flowchart illustrating an example of the RF power supply process for plasma processing in an embodiment.

[0027] Figure 16 This is a flowchart illustrating another example of the RF power supply process for plasma processing in an embodiment.

[0028] Figure 17 This is a diagram used to illustrate an example of shape anomalies produced during etching.

[0029] Explanation of reference numerals in the attached figures

[0030] 1. Plasma processing device

[0031] 10. Plasma processing chamber

[0032] 10a Dielectric Window

[0033] 10b sidewall

[0034] 10s plasma processing space

[0035] 11 Support section

[0036] 11a Substrate support

[0037] 11b Edge ring support

[0038] 12 Edge rings

[0039] 13 Gas Inlet Section

[0040] 13a Central Gas Injection Section

[0041] 13b Sidewall Gas Injection Section

[0042] 14 antennas

[0043] 20 Gas Supply Department

[0044] 21 Gas Source

[0045] 22 Flow Controller

[0046] 30 Power Supply Department

[0047] 31 RF Power Supply Department

[0048] 31a Source RF Generation Unit

[0049] 31b Bias RF Generation Unit

[0050] 32 DC Power Supply Section

[0051] 40 Exhaust System

[0052] W substrate Detailed Implementation

[0053] Hereinafter, embodiments (hereinafter referred to as "Embodiments") for carrying out the plasma processing apparatus and plasma processing method of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, the embodiments can be appropriately combined without contradicting the processing content. In the following embodiments, the same reference numerals are used to mark the same parts, and repeated descriptions are omitted.

[0054] (An example of shape anomalies produced during etching)

[0055] First, before describing the implementation method, an example of shape anomalies that occur during the etching of silicon films will be described. Figure 17 This is a diagram used to illustrate an example of shape anomalies produced during the etching of a silicon film.

[0056] In recent years, the technology of processing high aspect ratio holes has attracted attention in semiconductor manufacturing. One example is the high aspect ratio contact (HARC). 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 the aspect ratio of HARCs used in 3D NAND exceeds 65.

[0057] As the aspect ratio of the formed hole increases, it becomes difficult to form the hole perfectly perpendicular in the vertical direction. For example, as... Figure 17 As shown in (A), a phenomenon occurs where the tip tapers towards the vicinity of the bottom of the aperture. One possible reason for this phenomenon is that the incident direction of ions in the plasma becomes tilted relative to the depth direction of the aperture, making it difficult for ions to be transported to the bottom of the aperture. Alternatively, it is believed that ions become trapped within the aperture, hindering their continued travel.

[0058] In addition, such as Figure 17 As shown in (B), sometimes material removed by etching and reaction products generated by plasma accumulate on the substrate. When this material accumulates near the opening of the hole, the opening is sealed, making etching difficult. In addition, even if the opening is not completely sealed, ions have difficulty reaching the interior of the hole, resulting in distorted hole shape or difficulty in etching.

[0059] Additionally, sometimes etching can cause the edges of the mask openings to be cut off. In such cases, such as... Figure 17 As shown in (C), sometimes ions are deflected relative to the incident direction of the hole and hit the sidewall of the hole, causing the hole to deform into a barrel shape, a phenomenon known as bowing.

[0060] As mentioned above, the performance of high aspect ratio plasma processing is influenced by the free radicals, ions, and reaction products generated during plasma processing. Therefore, a technique is desired that can individually control the generated reaction species, free radicals, byproducts, etc., depending on the progress of plasma processing.

[0061] (Implementation Method)

[0062] In the embodiments described below, various physical quantities that are parameters of plasma processing are controlled by applying pulsed RF (high-frequency) power used during plasma generation. These controlled physical quantities include, for example, ion energy, ion incident angle, radical flux, ion flux, and the amount of byproducts.

[0063] The plasma processing apparatus described below is an ICP (Inductively Coupled Plasma) device. The control unit of the plasma processing apparatus in this embodiment controls the RF power (source RF signal, source power) supplied to the coil (antenna) using control signals. In one embodiment, high-density plasma is generated by supplying source RF signals. Furthermore, the supply of RF power can be achieved in various ways. For example, based on a pre-prepared program, the control unit of the plasma processing apparatus can switch power supply paths from multiple source RF generators, sequentially supplying source power of different power levels in a pulsed manner.

[0064] The period during which RF power is supplied to the coil is called the on (operating) period, and the period during which the RF power supply to the coil is stopped is called the off (non-operating) period. The source RF signal has a first state corresponding to the on period, such as the on state (source on state), and a second state corresponding to the off period, such as the off state (source off state). The source RF signal is a pulse signal that forms a cycle (source cycle) by the on period of the first state followed by the off period of the second state. The frequency of the source RF signal can be, for example, about 1 kHz to about 5 kHz.

[0065] Furthermore, the source RF signal in the embodiment can be converted into two or more levels (e.g., a first source power level and a second source power level) in the first state. For example, the first state of the source RF signal can have a first level that supplies a preset value of RF power to the coil and a second level that supplies a value of RF power lower than the first level to the coil. For example, the source RF signal can have a first level that supplies approximately 1000 watts of RF power to the coil and a second level that supplies approximately 250 watts of RF power to the coil. The RF power supplied by 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.

[0066] The control unit can also control the RF power (bias RF signal, bias power) supplied to the lower electrode of the plasma processing apparatus via control signals. In one embodiment, the supply of the bias RF signal generates ionic bonds on a substrate placed above the lower electrode, producing reactive species and free radicals. Furthermore, the supply of RF power can be achieved in various ways. For example, based on a pre-prepared program, the control unit of the plasma processing apparatus can switch power supply paths from multiple bias RF generation units, sequentially supplying bias power of different power levels in a pulsed manner.

[0067] The period during which RF power is supplied to the lower electrode is called the on-time, and the period during which the RF power supply to the lower electrode is stopped is called the off-time. The bias RF signal has a first state corresponding to the on-time, such as an on state (bias on state), and a second state corresponding to the off-time, such as an off state (bias off state). The bias RF signal is a continuous pulse signal that forms a cycle (bias cycle) consisting of the on-time of the first state and the off-time of the second state. The frequency of the bias RF signal can be, for example, about 1 kHz to about 5 kHz.

[0068] Furthermore, the bias RF signal in the embodiment can be converted to more than two levels in the first state (e.g., a first bias power level and a second bias power level). For example, the first state of the bias RF signal can have a first level that supplies a preset value of RF power to the lower electrode and a second level that supplies a value of RF power lower than the first level to the lower electrode. For example, the bias RF signal can have a first level that supplies approximately 250 watts of RF power to the lower electrode and a second level that supplies approximately 92.5 watts of RF power to the lower electrode. The first level and the second level can be high level and low level, respectively.

[0069] Hereinafter, we will first describe an example of the configuration of a plasma processing apparatus that performs plasma processing.

[0070] (Example of the configuration of the plasma processing apparatus in the embodiment)

[0071] Figure 1 This is a conceptual diagram of the configuration of the plasma processing apparatus according to the embodiment. Figure 2 It means Figure 1 A schematic longitudinal sectional view of an example of the configuration of a plasma processing device. (Refer to...) Figure 1 and Figure 2 The plasma processing apparatus 1 described in the embodiment is further explained. Figure 2 The plasma processing device 1 shown is a so-called inductively-coupled plasma (ICP) device that generates inductively-coupled plasma.

[0072] 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. Furthermore, the plasma processing apparatus 1 includes a support portion 11, an edge ring 12, a gas inlet portion 13, and an antenna 14 disposed within the plasma processing space 10s. The support portion 11 includes a substrate support portion 11a and an edge ring support portion 11b. The edge ring support portion 11b is configured to surround the outer peripheral surface of the substrate support portion 11a. The antenna 14 is disposed above or above the plasma processing chamber 10 (dielectric window 10a).

[0073] The substrate support portion 11a has a substrate support region on which a substrate is supported. In one embodiment, the substrate support portion 11a includes an electrostatic chuck (electrostatic suction cup) and a lower electrode. The lower electrode is disposed below the electrostatic chuck. The electrostatic chuck serves as the substrate support region. Additionally, although not shown in the figures, in one embodiment, the substrate support portion 11a may include a temperature control module that adjusts 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-regulating fluid such as a refrigerant or heat transfer gas flows through the flow path.

[0074] The edge ring 12 is configured to surround the substrate W on the upper surface of the peripheral portion of the lower electrode. The edge ring support portion 11b has an edge ring support region, and the edge ring 12 is supported on the edge ring support region.

[0075] The gas inlet 13 supplies at least one type of 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 section 13a and / or a sidewall gas injection section 13b. The central gas injection section 13a is disposed above the substrate support section 11a and is installed in the central opening formed in the dielectric window 10c. The sidewall gas injection sections 13b are installed in a plurality of sidewall openings formed in the sidewall of the plasma processing chamber 10.

[0076] 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 processing gases from their respective gas sources 21 to the gas inlet unit via their respective flow controllers 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsed flow rates of the one or more processing gases.

[0077] The power supply unit 30 includes an RF power supply unit 31 integrated with the plasma processing chamber 10. The RF power supply unit 31 supplies RF signals (RF power, such as source RF signals and bias RF signals) to the lower electrode and antenna 14. Plasma is thus generated using at least one processing gas supplied to the plasma processing space 10s. In one embodiment, the RF signal is pulsed. A pulsed RF signal, pulsed RF power, pulsed source RF signal, and pulsed bias RF signal are examples of pulsed RF signals.

[0078] In one embodiment, the RF power supply unit 31 includes a source RF generation unit 31a and a bias RF generation unit 31b. The source RF generation unit 31a and the bias RF generation unit 31b are coupled to the plasma processing chamber 10. In one embodiment, the source RF generation unit 31a is coupled to the antenna 14, and the bias RF generation unit 31b is coupled to a lower electrode within the substrate support unit 11a. The source RF generation unit 31a generates 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 supplied to the antenna 14. The bias RF generation unit 31b generates at least one bias RF signal. The bias RF signal has a frequency lower 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 supplied to the lower electrode. Furthermore, in various embodiments, the amplitude of at least one of the source RF signal and the bias RF signal can be pulsed or modulated. Amplitude modulation can be used to pulse the amplitude of an RF signal between an on and off state or between two or more different on states.

[0079] Additionally, the power supply unit 30 may include a DC power supply unit 32. In one embodiment, the DC power supply unit 32 may apply at least one DC voltage to the lower electrode. In another embodiment, at least one DC voltage may be applied to another electrode, such as an electrode within an electrostatic chuck. In one embodiment, the DC signal may be pulsed. Furthermore, the DC power supply unit 32 may be provided based on the RF power supply unit 31, or it may be provided as a replacement for the bias RF generation unit 31b.

[0080] 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 unit 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 generation unit may be connected to both the outer coil and the inner coil, while other RF generation units may be connected to the outer coil and the inner coil separately.

[0081] The exhaust system 40 can be connected, for example, to an exhaust port (gas outlet) located 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.

[0082] In one implementation, the control unit (and...) Figure 2The control unit 50 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various steps described herein. The control unit can be configured to control the various elements of the plasma processing apparatus 1, causing the various steps described herein to be performed. In one embodiment, part or all of the control unit may be included in the plasma processing apparatus 1. The control unit may, for example, include a computer. The computer includes, for example, a processing unit (CPU), a storage unit, and a communication interface. The processing unit performs various control actions based on programs stored in the storage unit. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface can communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0083] (Plasma processing flow of the implementation method)

[0084] Figure 3 This is a flowchart illustrating an example of a plasma processing procedure in an implementation method. Figure 3 The plasma processing shown is capable of Figure 1 , 2 It is implemented in plasma processing device 1. Figure 4 This is a diagram illustrating an example of a substrate processed by plasma processing according to an embodiment.

[0085] First, a substrate W is provided inside the plasma processing chamber 10 (step S31). The substrate W is, for example, as shown in... Figure 4 The diagram shows a substrate layer L1, an etchable target layer (Si layer) L2, and a mask MK sequentially formed on a silicon substrate. A recess OP is pre-formed on the substrate W (see reference). Figure 4(A)). Furthermore, the recess OP can be formed within the plasma processing apparatus 1. Next, the plasma processing apparatus 1 is controlled by the control unit to supply etching gas from the gas supply unit 20 into the plasma processing chamber 10. Additionally, the plasma processing apparatus 1 is controlled by the control unit to supply RF power to the lower electrode and antenna 14 (coil) from the RF power supply unit 31 (source RF generation unit 31a and bias RF generation unit 31b). At this time, the RF power supply unit 31 supplies RF power at a level corresponding to the waveform of the RF signal to the lower electrode and antenna 14. The waveform of the RF signal will be described later. By supplying RF power, plasma is generated to supply the gas to the plasma processing chamber 10, and plasma etching (step S32) is performed. Through plasma etching, the bottom of the recess OP formed on the mask MK of the substrate W is removed, and the recess OP gradually deepens (see reference). Figure 4 (B)). Then, the control unit of the plasma processing apparatus 1 determines whether a preset processing time has elapsed (step S33). When the preset processing time has elapsed, the bottom of the recess OP reaches the base layer L1, becoming Figure 4 The shape shown in (C) is correct. If it is determined that the processing time has not yet elapsed (step S33, No), the control unit returns to step S32 to continue plasma etching. On the other hand, if it is determined that the processing time has elapsed (step S33, Yes), the control unit terminates the process.

[0086] In this embodiment, the plasma processing apparatus 1 supplies a source RF signal and a bias RF signal during plasma etching in step S32. The plasma processing apparatus 1 controls the amount of ions and free radicals in the plasma, as well as the amount of byproducts generated by plasma etching, based on 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 explained.

[0087] (Example of RF signal waveform)

[0088] Figure 5 This is a diagram illustrating an example of the waveform of the RF signal used for RF power supply in the plasma processing of the embodiment.

[0089] Figure 5 The timing diagram 100 shown illustrates the source power (source RF signal) P. S and bias power (bias RF signal) P B Source power P S This is the RF power supplied from the source RF generation unit 31a to the antenna (coil) 14. Additionally, the bias power P... BThis is the RF power supplied from the bias RF generation unit 31b to the lower electrode in the substrate support unit 11a. The source RF generation unit 31a generates source power P, for example, based on a control signal supplied from the control unit. S The generated source power P S It is supplied to the coil. The bias RF generation unit 31b generates bias power P, for example, based on a control signal supplied from the control unit. B The generated bias power P S It is supplied to the lower electrode.

[0090] exist Figure 5 In this context, period 150 represents one cycle of the source RF signal. Period 160 represents one cycle of the bias RF signal. Furthermore, unless otherwise specified in the following explanation, periods 1501, 1502, ... will be collectively referred to as period 150, and periods 1601, 1602, ... will be collectively referred to as period 160. One cycle refers to the period from the rise of the pulse signal to the next rise, i.e., the combined on and off periods. The source RF signal and the bias RF signal are pulse signals of the same frequency.

[0091] The source RF signal repeatedly functions as an "on" state (first state) supplying RF power to the coil and an "off" state (second state) supplying no RF power to the coil. When the source RF signal is in the "on" state, the source power P... S Power is supplied to the coil. When the source RF signal is off, no power is supplied to the coil; that is, the supply of RF power to the coil is stopped.

[0092] The bias RF signal repeatedly functions as an "on" state (first state) to supply RF power to the lower electrode and an "off" state (second state) to not supply RF power to the lower electrode. Figure 5 In the example, when the bias RF signal is on, the bias power P B Power is supplied to the lower electrode. When the bias RF signal is off, no power is supplied to the lower electrode, that is, the supply of RF power to the lower electrode is stopped.

[0093] exist Figure 5 In this context, the rise of the bias RF signal is delayed by a period D1 relative to the rise of the source RF signal. The bias RF signal rises after the source RF signal transitions from an on state to an off state, and then rises during the off state of the source RF signal. As described above, the start time of the period of the source RF signal and the start time of the period of the bias RF signal are staggered by a period D1. Figure 5 In the example, the bias off state (t3) in the previous bias loop transitions to the bias on state P in the first bias loop 1601. BLThe transition time (t4) is relative to the source-on state P in the first source loop 1501 corresponding to the first bias loop 1601. SH The transition time from 0 to t1 is delayed. Additionally, as... Figure 5 As shown in t3, the source turn-off period and the bias turn-off period partially overlap. Furthermore, as... Figure 5 As shown in t6, the bias turn-on period in the first bias loop 1601 partially overlaps with the source turn-on period in the second source loop 1502.

[0094] Furthermore, the lengths of the on and off periods of the source RF signal differ from the lengths of the on and off periods of the bias RF signal. Figure 5 In this example, the duty cycle (the ratio of the on-time to the length of one cycle) of the source RF signal is approximately 40%. Additionally, the duty cycle of the bias RF signal is approximately 60%. However, the duty cycles of the source RF signal and the bias RF signal are not limited to the values ​​described above. Furthermore, the source RF signal and the bias RF signal may have the same duty cycle.

[0095] As described above, the source RF signal and the bias RF signal undergo state transitions (state transitions) respectively. The timing of the state transition of the source RF signal, the initial transition point (transition initial), and the power level of the transition target (transition target) can be different from those of the bias RF signal.

[0096] Additionally, there exists a period T during which neither the source RF signal nor the bias RF signal is supplied. OFF The period T during which both the source RF signal and the bias RF signal are supplied. ON Source power P S and bias power P B The supply method is shifted in the following 5 stages.

[0097] (1) First stage ( Figure 5 (ST1):

[0098] The first stage consists of the parameter set {P} S1 P B1 ,t1} is defined. Here, P S1 The source power P supplied in the first stage S The value of P. B1 The bias power P supplied in the first stage B The value of t1. t1 represents the length of the first phase. Here, the following relationship holds.

[0099] P S1 >0

[0100] P B1>0

[0101] t1>0

[0102] In the first stage, it will have a high power level P SH The source power P (first source power level) S The power is supplied to the coil and will have a high power level P. BH The bias power P (second bias power level) B The plasma is supplied to the lower electrode. During the first stage, period t1, RF power is supplied to the upper and lower parts of the plasma processing device 1 to generate plasma, in which ions and free radicals are generated. During the etching process, etching is performed during period t1.

[0103] (2) Second stage ( Figure 5 (ST2):

[0104] The second stage consists of the parameter set {P} S2 P B2 ,t2} is defined. Here, P S2 The source power P supplied in the second stage S The value of P. B2 The bias power P supplied in the second stage B The value of t2. t2 represents the length of the second phase. Here, the following relationship holds.

[0105] P S1 >P S2 >0

[0106] P B1 =0

[0107] t2>0

[0108] In the second stage, a low power level P will be used. SL (Second source power level) source power P S The power P supplied to the coil stops the bias. B The supply. The second stage, for example, is... Figure 5 During period t2, RF power is supplied only to the upper part of plasma processing device 1. Because RF power is not supplied to the lower electrode side, no force for introducing ions is generated on the lower electrode side. In addition, the amount of ions and free radicals generated is also reduced.

[0109] (3) The third stage ( Figure 5 (ST3):

[0110] The third stage consists of the parameter set {P} S3 P B3 ,t3} is defined. Here, P S3The source power P supplied in the third stage S The value of P. B3 The bias power P supplied in the third stage B The value of t3. t3 represents the length of the third phase. Here, the following relationship holds.

[0111] P S3 =P B3 =0

[0112] t3>0

[0113] In the third stage, the source power P S and bias power P B All supplies will cease. The third phase, for example, is... Figure 5 During period t3, plasma generation within the plasma processing apparatus 1 ceases, and the plasma processing space is vented for 10 seconds using the exhaust system 40. At this time, the plasma generated by etching and retained in the recess ( Figure 4 The byproducts at the bottom of the plasma treatment chamber are degassed. The amount of ions and free radicals in the plasma treatment space is also reduced within 10 seconds.

[0114] (4) Fourth stage ( Figure 5 (ST4):

[0115] The fourth stage consists of the parameter set {P} S4 P B4 ,t4} is defined. Here, P S4 The source power P supplied in the fourth stage S The value of P. B4 The bias power P supplied in the fourth stage B The value of t4 represents the length of the fourth phase. Here, the following relationship holds.

[0116] P S4 =0

[0117] P B1 >P B4 >0

[0118] t4>0

[0119] In the fourth stage, the source power P S When the supply stops, it has a low power level P. BL The bias power P (first bias power level) B The supply begins. During the fourth phase, period t4, no source power P is supplied. S Therefore, no plasma generation occurs; however, the ions generated in the first and second stages remain in the plasma processing space for 10 seconds. Therefore, by biasing the power P...B The supply introduces ions into the recess ( Figure 4 The bottom of the OP (op-shaped) recess. In addition, the incident angle of the ions is closer to vertical, which can promote vertical etching of the sidewalls of the OP recess.

[0120] (5) Fifth stage ( Figure 5 (ST5):

[0121] The fifth stage consists of the parameter set {P} S5 P B5 ,t5} is defined. Here, P S5 The source power P supplied in the fifth stage S The value of P. B5 The bias power P supplied in the fifth stage B The value of t5 represents the length of the fifth stage period. Here, the following relationship holds.

[0122] P S5 =0

[0123] P B1 =P B5 >P B4 >0

[0124] t5>0

[0125] In the fifth stage, the source power P S When the supply stops, the bias power P B The power level is from Low power level P BL To High power level P BH The process involves an increase (transition). Therefore, as a preparatory stage for the first stage, the ion energy increases within 10 seconds in the fifth stage of plasma processing. The amount of free radicals and byproducts continues to decrease as in the third stage.

[0126] After the fifth stage, it returns to the first stage, with a source power P at a high power level. S and bias power P with high power level B The bias power P is applied in an overlapping manner. This cycle is repeated, with the bias power P applied beforehand in the fifth stage. B Under the condition of generating ion energy through the application of [something], the first stage of applying source power P begins. S Ions and free radicals are generated. Therefore, the etching in the first stage is promoted, and ions are effectively introduced into the bottom of the recessed OP. Furthermore, venting of byproducts in the third stage further promotes etching.

[0127] As described above, using with Figure 5The source RF signal and bias RF signal of the pulse waveform can control the state of ions, free radicals and byproducts in the plasma processing space within 10 seconds and achieve vertical etching. Therefore, it is possible to suppress shape anomalies caused by etching, thereby improving the processing performance of the plasma.

[0128] Among them, Figure 5 In the example, the source power P S The value P is taken when the period t1 is in the on state. SH During the subsequent period t2, when the device is in the ON state, the value is taken as P. SL Additionally, the bias power P B The value P is taken during the period t4. BL During the subsequent period, t5 is directed towards value P. BH Transformation. As described above, in the plasma processing method of this embodiment, in order to control the various physical quantities of the plasma, the on / off state of the source RF signal can be controlled at two levels (three levels including the off state). Additionally, in the plasma processing method of this embodiment, the on / off state of the bias RF signal can be controlled at two levels (three levels including the off state). As described above, by varying the RF power values ​​applied to the coil and the lower electrode in stages, more precise adjustments to the plasma processing parameters can be made.

[0129] exist Figure 5 In the example, the following relationship holds true.

[0130] 0 <P SL <P SH

[0131] 0 <P BL <P BH

[0132] The frequencies of the source RF signal and the bias RF signal are 0.1kHz to 5kHz.

[0133] Duty cycle of the source RF signal: approximately 40%

[0134] Duty cycle of the bias RF signal: approximately 60%

[0135] P SH The length of the period: P SL The length of the period = 1:3

[0136] P BH The length of the period: P BL The length of the period = 1:2

[0137] t1:t2:t3:t4:t5=1:3:1:4:1

[0138] However, this embodiment can be used not only in the case where the described relationship holds, but also in other relationships. Other relationships will be described as variations below.

[0139] Figures 6-9 This is a graph illustrating the changes in physical quantities within the plasma processing chamber 10 corresponding to an example waveform of an RF signal. (Refer to...) Figures 6-9 Explain the changes in physical quantities corresponding to the waveform of the RF signal.

[0140] Figure 6 Waveform Example 1 has a "first stage" where both source power and bias power are supplied simultaneously, a "second stage" where only source power is supplied, and a "fourth stage" where only bias power is supplied. Compared to the waveform examples of the described embodiment, Waveform Example 1 lacks a "third stage" where no RF power is supplied and a "fifth stage" where the bias power level fluctuates before the rise of the source RF signal. In the case of Waveform Example 1, in the first stage, ion flux, free radical flux, and ion energy all increase, and the amount of byproducts also increases. Then, in the second stage, the amount of each gradually decreases. By stopping the supply of bias power, the ion energy becomes approximately zero. In the fourth stage, the ion energy increases compared to the first stage due to the supply of bias power. On the other hand, the ion flux, free radical flux, and amount of byproducts do not change significantly from the second stage onwards.

[0141] Figure 7 The waveform in Example 2 is roughly the same as Figure 6 The waveform is the same as in Example 1. However, the value of the bias power in the fourth stage (P) is different. BM The value of the bias power (P) in waveform example 1 is compared with that of the bias power in waveform example 1. B L) increased compared to. In Figure 7 In the example, ion flux, free radical flux, and the amount of byproducts are related to Figure 6 The waveform example 1 is roughly the same. However, the ion energy in the fourth stage increases compared to waveform example 1. Figure 7 (C1). Furthermore, in Figure 7 In (C), in relation to Figure 6 On the same dashed line as (C), use only with Figure 6 The thick dashed line C1 represents the different parts of (C). Figure 7 Changes in ion energy under condition (A).

[0142] Figure 8 Waveform Example 3 and Figure 6 Compared to the waveform in Example 1, the first stage increases, causing the second stage to shorten by the corresponding amount. Figure 8 In the example, the amounts of ion flux and free radical flux are related to the first and second stages. Figure 6 The number of cases increased by comparison ( Figure 8In the middle, C2 and C3). On the other hand, the ion energy and the amount of byproducts did not change significantly. Furthermore, the thick dashed lines C2 and C3, like C1, only indicate the relationship with... Figure 6 Different parts.

[0143] Figure 9 Waveform Example 4 and Figure 6 Compared to waveform example 1, this differs in that a fifth stage is included. The power level of the fifth stage is lower than the power level P of the fourth stage. BL To P BH Transformation. In Figure 9 In the example, ion flux, free radical flux, and the amount of byproducts are related to Figure 6 The waveform is roughly the same as in Example 1. The ion energy is related to the switching bias power P in the fifth stage. B Correspondingly, in the fifth stage, ( Figure 9 (C4) Figure 9 The thick dashed line C4 in the text only indicates that it is related to... Figure 6 (D) different parts.

[0144] In addition, using from Figures 6 to 9 When etching is performed using the RF power shown in the waveform examples, the variation in the dimension (critical dimension) from the top to the bottom of the recess is larger in waveform examples 1 and 3 compared to waveform example 2. That is, as in the fourth stage of waveform example 2, when a slightly higher level of bias power is supplied, holes of more uniform size can be formed in the longitudinal direction during deep hole etching. On the other hand, as shown in waveform example 3, when the ratio of the length of the first stage to the length of the second stage is changed, mask consumption is reduced, and etching of the target film can be selectively achieved. Through this control, the state changes of ions and free radicals in the plasma processing space within 10 seconds, especially near the substrate being processed, affect the performance of the plasma processing, depending on the waveform of the RF power. Therefore, by adjusting the waveform of the RF signal, the performance of the plasma processing, i.e., the shape of the pattern formed by the plasma processing, can be controlled.

[0145] also, Figures 6-9 The waveform examples 1 to 4 may include the third stage of this embodiment, namely, the stage in which RF power is not supplied to either the coil or the lower electrode. By introducing the third stage in which no RF power is supplied, the amount of byproducts generated within 10 seconds of the plasma processing space can be further reduced, and the etching accuracy in the vertical direction can be improved.

[0146] However, this embodiment is not limited to the description. Figure 5 The waveform can achieve the same effect through variation example two. Below, while referring to... Figures 10-14 Let's explain the variations 1 to 5.

[0147] (Variation Example 1)

[0148] Figure 10 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 1. Figure 10 The timing diagram 200 shown represents the source power P. S and bias power P B First, at the start of period t1, the source power P is applied. SH and bias power P BH During period t1, the source power P SH and bias power P BH A specified level is applied in an overlapping manner. Then, during period t3, the source power P... S and bias power P B Both stopped supplying (during period T) OFF Next, during period t4, the bias power P BH The supply begins. Then, at the moment when the next cycle begins (1502), the source power P... SH The supply begins, source power P SH and bias power P BH Applying overlappingly (during T) ON ).

[0149] and Figure 5 The waveform examples are different, in Figure 10 In timing diagram 200, there is no second stage, i.e., source power P. S The supply to the coil continues, and the bias power P B The period when supply ceases. Additionally... Figure 10 The timing diagram 200 does not have a fifth stage, i.e., at source power P. S Supply front bias power P B The level changes during this stage. Therefore, in cases where pattern formation for the exhaust of byproducts (third stage) is suitable without adjusting the amount of ions and free radicals, Modified Example 1 can be used. Furthermore, Modified Example 1 can be used when no ion energy is generated before plasma generation.

[0150] (Variation Example 2)

[0151] Figure 11 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 2. Figure 11 In the timing diagram 210 shown, firstly, during period t1, the source power P is applied. SH and bias power P BH During the subsequent period t2, the source power P S The level from P SHTo P SM Changes. Additionally, at the start of period t2, the bias power P... BH The supply stops. Then, during period t3, the source power P... SM The supply stops. Therefore, during period t3, the source power P S and bias power P B Neither of them will be supplied (during period T) OFF Then, during period t4, the bias power P BM The supply begins. During period t4, the supply level P... BM bias power P B Then, during period t5, the bias power P B The level from P BM To P BH Changes. Then, at the bias power P BH Under the condition that the supply continues, in the next cycle 1502, the power of the supply source P SH Thus, the source power P is supplied in an overlapping manner. SH and bias power P BH (period T) ON ).

[0152] and Figure 5 Compared to the waveform example, in modified example 2, the source power P S The level is set to P SH and P SM This is different. Furthermore, the source power P S The level is set according to level P. SH P SM P S The sequence of L changes from high level to low level. Additionally, in variation 2, the bias power P... B The level is set to P BH and P BM This point is consistent with Figure 5 The waveform examples are different. Furthermore, the bias power P... B The level is set according to level P. BH P BM P B The sequence of L changes from high to low. In the case of variation 2, the source power P... S and bias power P B The on / off state is set to two levels. However, the lower of the two levels is set to the same level as... Figure 5 Compared to the case where it becomes a high level.

[0153] For example, before and after the third stage of venting the byproducts, if the electron density Ne, radical density Nr, electron temperature Te, ion energy εi, etc., need to be maintained at a high level, as shown in Modified Example 2, the source power P is... S and bias power P B The voltage levels for the multiple on states can be set to a higher value.

[0154] In variation example 2, it is also related to Figure 5 Similarly, in the waveform example, the rise of the bias RF signal is delayed by D1 from the rise of the source RF signal. Additionally, there is a source power P. S and bias power P B During the period T when neither of them is supplied OFF Additionally, there exists a source power P. S and bias power P B The supply period T of both parties ON During T ON This is the period from the moment the source RF signal rises to the moment the bias RF signal falls.

[0155] (Variation Example 3)

[0156] Figure 12 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 3. Figure 12 In the timing diagram 220 shown, firstly, during period t1, the source power P can be supplied. SH and bias power P BM Next, during period t2, the source power P S The level from P SH To P SM Changes. Additionally, during period t2, the bias power P... BM The supply stops. Then, during period t3, the source power P... SM The supply ceases. No source power P is supplied during period t3. S and bias power P B either of (T) OFF Then, during period t4, the bias power P BH The supply begins. During period t4, the supply level P... BH bias power P B Then, during period t5, the bias power P B The level from P BH To P BM Changes. Then, the bias power P BM Under the condition that the supply continues, at the beginning of cycle 1502, the power P of the supply source is... SH This makes the source power P SH and bias power PBM Overlapping supply (period T) ON ).

[0157] Modification Example 3 and Figure 11 The variation of Example 2 is largely the same. However, in Example 3, the bias power P... B The order of level transitions differs from that in Modified Example 2. In Modified Example 2, the bias power P during the time period t1 is... B The level is P BH During the period t4, P is... BM During the period t5, P is... BH In this regard, in variation 3, the bias power P during the time period t1 is... B The level is P BM During the period t4, P is... BH During the period t5, P is... BM In variation 2, the bias power P B The voltage level changes sequentially from the first stage to the fifth stage: high level, off state, low level, high level. In variation 3, the bias power P... B The voltage level changes in the order of low level, off state, high level, low level from the first stage to the fifth stage.

[0158] For example, the waveform of Modified Example 3 is suitable for plasma treatment that introduces ions to the bottom of the recessed OP by increasing the ion energy in the third stage.

[0159] (Variation Example 4)

[0160] Figure 13 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 4. Figure 13 In the timing diagram 230 shown, firstly, during period t1, the source power P is applied. SM and bias power P BH Next, during period t2, the source power P S The level from P SM To P SH Changes. Additionally, during period t2, the bias power P... BH The supply stopped. Then, during period t3, the source power P... SH The supply ceases. During the period t3, the source power P S and bias power P B Neither of them will be supplied (T) OFF Then, during period t4, the bias power P BM The supply begins. During the period t4, the supply level P... BM bias power PB Then, during period t5, the bias power P B The level from P BM To P BH Changes. Then, the bias power P BH Under the condition that the supply continues, when it becomes period 1502, the power P of the supply source is... SM Thus, the source power P is supplied in an overlapping manner. SM and bias power P BH (period T) ON ).

[0161] Variation Example 4 and Figure 11 The variation of Example 2 is largely the same. However, in Example 4, the source power P... S The order of level changes is different from that in Modified Example 2. In Modified Example 2, the source power P during the time period t1 is... S The level is P SH During period t2, P is... SM In this regard, in variation 3, the bias power P during the time period t1 is... B The level is P SM During period t2, P is... SH In variation example 2, the source power P S The voltage level changes in the order of high, low, and off from the first stage to the third stage, but remains unchanged from the third stage to the fourth stage. In variation 4, the source power P... S The voltage level changes in the order of low, high, and off from the first stage to the third stage, but remains unchanged from the third stage to the fourth stage.

[0162] Modification 4, for example, is a treatment that is preferably a gradual increase in the amount of ions and free radicals in the first stage, rather than a treatment that causes a sharp increase.

[0163] (Variation Example 5)

[0164] Figure 14 This is a diagram showing an example of the waveform of the RF signal used for RF power supply in the plasma processing of Modified Example 5. Figure 14 In the timing diagram 240 shown, firstly, during period t1, the source power P is applied. SM and bias power P BM Next, during period t2, the source power P S The level from P SM To P SH Changes. Additionally, during period t2, the bias power P... BM The supply stops. Then, during period t3, the source power P... SH The supply ceases. During the period t3, the source power P Sand bias power P B Neither of them will be supplied (T) OFF Then, during period t4, the bias power P BH The supply begins. During the period t4, the supply level P... BH bias power P B Then, during period t5, the bias power P B The level from P BH To P BM Changes. Then, at the bias power P BM Under the condition that the supply continues, when it becomes period 1502, the power P of the supply source is... SM Thus, the source power P is supplied in an overlapping manner. SM and bias power P BM (T ON ).

[0165] Variation 5 is to Figure 12 The bias power P of variation example 3 B and Figure 13 The source power P of variation example 4 S The waveform formed by the combination. The bias power P in variation example 3. B The levels change sequentially from the first stage to the fifth stage: low level (first stage), off state (second and third stages), high level (fourth stage), and low level (fifth stage). Additionally, the source power P in variation 4... S The waveform changes sequentially from stage one to stage five: low level (stage one), high level (stage two), and off state (stages three through five). Therefore, the waveform in variation 5 changes sequentially from stage one to stage five, {P S P B Press {P} SM P BM}、{P SH P BOFF}、{P SOFF P BOFF}、{P SOFF P BH}、{P SOFF P BM The order of changes is as follows. Furthermore, in this case, where a waveform contains two levels in the on-state, for convenience, one level is referred to as high level and the other as low level, rather than medium level. Additionally, the source power P... S The off state is represented by P SOFF The bias power P B The off state is represented by P BOFF .

[0166] Variation 5 is suitable for a process in which the ion energy is temporarily increased and then decreased in the fourth stage to begin etching.

[0167] (RF power supply process)

[0168] Figure 15 This is a flowchart illustrating an example of the RF power supply process for plasma processing in an embodiment. Figure 15 The process shown in step 1500 is, for example, in... Figure 3 Execute in step S32.

[0169] First, under the control of the control unit, the RF power supply unit 31 performs the first stage of RF power supply (step S1510). The first stage of RF power supply is determined by the processing parameters {P} of the first group. S1 P B1 ,t1} is defined. Here, P S1 >0 and P B1 >0, t1>0.

[0170] Next, under the control of the control unit, the RF power supply unit 31 performs the second stage of RF power supply (step S1520). The second stage of RF power supply is determined by the second set of processing parameters {P}. S2 P B2 ,t2} is defined. Here, P S2 >0 and P B2 =0, t2≧0.

[0171] Next, under the control of the control unit, the RF power supply unit 31 performs the third stage of RF power supply (step S1530). The third stage of RF power supply is determined by the third set of processing parameters {P}. S3 P B3 ,t3} is specified. Here, P S3 =0 and P B3 =0, t3>0.

[0172] Next, under the control of the control unit, the RF power supply unit 31 performs the fourth stage of RF power supply (step S1540). The fourth stage of RF power supply is determined by the fourth set of processing parameters {P}. S4 P B4 ,t4} is specified. Here, P S4 =0 and P B4 >0, t4>0.

[0173] Next, under the control of the control unit, the RF power supply unit 31 performs the fifth stage of RF power supply (step S1550). The fifth stage of RF power supply is determined by the fifth set of processing parameters {P}. S5 P B5 ,t5} is specified. Here, PS5 =0 and P B5 >0、t5≧0.

[0174] Steps S1510 to S1540 are executed as a loop. Then, after step S1540, the loop returns to step S1510 and is executed again.

[0175] Figure 16 This is a flowchart illustrating another example of the RF power supply process for plasma processing in an embodiment. Figure 16 The process shown in 1600 is, for example, in Figure 3 Execute in step S32.

[0176] First, under the control of the control unit, the RF power supply unit 31 supplies source power P to the antenna (coil) 14. S Simultaneously, a bias power P is supplied to the lower electrode. B Thus, plasma is generated within 10 seconds in the plasma processing space. Furthermore, the plasma contains ions and free radicals (step S1610).

[0177] Next, under the control of the control unit, the RF power supply unit 31 stops supplying bias power P to the lower electrode. B Additionally, the RF power supply unit 31 supplies source power P to the antenna (coil) 14. S The value changes. For example, the RF power supply unit 31 makes the source power P change. S Decrease or increase. As a result, the RF power supply unit 31 adjusts the amount of ions and free radicals contained in the plasma within the plasma processing space for 10 seconds (step S1620).

[0178] Next, under the control of the control unit, the RF power supply unit 31 provides bias power P. B When the supply to the lower electrode is stopped, the power P of the stop source is... S Supply to the coil. Then, the exhaust treatment of the plasma processing space for 10 seconds by the exhaust system 40 can reduce the amount of by-products in the plasma processing space for 10 seconds (step S1630).

[0179] Next, under the control of the control unit, the RF power supply unit 31 supplies bias power P to the lower electrode. B Source power P S The supply remains in a stopped state. Generation is achieved by bias power P. B The resulting force applied to the lower electrode (step S1640).

[0180] Steps S1610 to S1640 are executed as a loop. Then, after step S1640, the loop returns to step S1610 and is executed again.

[0181] Furthermore, some of the embodiments and variations described herein may be appropriately modified. Hereinafter, some designed variations are described.

[0182] (Other implementation methods)

[0183] Source power P S It can also be alternating current (AC) power. Additionally, the source power P... S It can be either high-frequency (RF) power or VHF (Very High Frequency) power. Source power P S For example, it could be RF power ranging from approximately 60MHz to approximately 200MHz. Additionally, the source power P... S For example, it could be RF power ranging from approximately 25 MHz to approximately 60 MHz. Source power P S For example, it could be 27MHz. In this embodiment, the source power P S Generates inductively coupled plasma (ICP). Source power P S For example, it can be combined with a helical antenna to generate plasma.

[0184] Bias power P B It can also be alternating current (AC) power. Additionally, the bias power P... B It can also be a direct current (DC) pulse power. Bias power P B It can also be any of RF (Radio Frequency) power, HF (High Frequency) power, or MF (Medium Frequency) power. Bias power P B For example, it can be the power at frequencies ranging from approximately 200 kHz to approximately 600 kHz. Bias power P B For example, it could be 400kHz. Additionally, the bias power P... B For example, the power range could be from approximately 600 kHz to approximately 13 MHz.

[0185] Source power P S and bias power P B Each can be applied as a single pulse or as a continuous pulse in each cycle. For example, in the first stage, the source power P applied during period t1... S1 It can be a single pulse or a continuous pulse. Similarly, the bias power P applied during period t2... B2 It can be a single pulse or a continuous pulse.

[0186] The duty cycles of the source RF signal and the bias RF signal can be set independently within the range of approximately 3% to approximately 90%.

[0187] For example, in the case of three-level waveforms, the duty cycle of the high-level on-state of the source RF signal can be set within the range of approximately 5% to approximately 50%. Furthermore, the duty cycle of the low-level on-state of the source RF signal can be set within the range of 0% to approximately 45%. Additionally, the duty cycle of the off-state of the source RF signal can be set within the range of approximately 5% to approximately 90%.

[0188] Furthermore, the duty cycle of the high-level on state of the bias RF signal can be set within the range of approximately 5% to approximately 50%. Additionally, the duty cycle of the low-level on state of the bias RF signal can be set within the range of approximately 0% to approximately 45%. Furthermore, the duty cycle of the off state of the bias RF signal can be set within the range of approximately 5% to approximately 90%.

[0189] Furthermore, the length of the period during which both the source RF signal and the bias RF signal are simultaneously off can be set within a duty cycle range of approximately 5% to approximately 90%. This period can be set, for example, within a range of approximately 0 microseconds to approximately 500 microseconds, more preferably within a range of approximately 10 microseconds to approximately 50 milliseconds. Additionally, this period is preferably set with the duty cycle of the source RF signal and the bias RF signal within a range of approximately 10% to approximately 50%.

[0190] The plasma processing chamber 10 is supplied with gas at a flow rate selected according to a pre-set plasma processing parameters. In one cycle comprising the first, second, third, fourth, and fifth stages, 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). Additionally, the supplied gas may include, for example, rare gases such as helium (He) and argon (Ar). Furthermore, the supplied gas may include, for example, oxygen (O2), methane (CF4), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), chlorine (Cl2), carbon tetrachloride (CCl4), etc.

[0191] In the plasma processing described in this embodiment, the byproducts generated can be compounds containing one or more elements included in the composition of the gas within the plasma processing chamber 10 and the substrate. For example, when using a silicon substrate and HBr gas, byproducts containing SiBrx can be formed. In addition, silicon-containing residues such as silicon fluoride (SiFx) and silicon chloride (SiClx), and carbon-containing residues such as fluorocarbon (CFx) and hydrofluorocarbon compounds (CHxFy) (when processing with photoresist, organic films, and precursors) are also formed as byproducts.

[0192] (Effects of the implementation method)

[0193] As described above, the plasma processing apparatus of this embodiment includes a plasma processing chamber, a substrate support, a source RF generation unit, and a bias RF generation unit. The substrate support is disposed within the plasma processing chamber. The source RF generation unit is combined with the plasma processing chamber to generate a pulsed source RF signal comprising multiple source cycles. Each source cycle has a source operating state during a period of source operation and a source non-operation state during a period of source non-operation following the source operating period. The bias RF generation unit is combined with the substrate support to generate a pulsed bias RF signal. The pulsed bias RF signal has multiple bias cycles having the same pulse frequency as the multiple source cycles. Each bias cycle has a bias operating state during a period of bias operation and a bias non-operation state during a period of bias non-operation following the bias operating period. The transition time to the bias operating state in each bias cycle is delayed relative to the transition time to the source operating state in the corresponding source cycle. The source turn-off period overlaps with the bias non-operation period. The bias operating period in each bias cycle overlaps with the source operating period in the next source cycle. Therefore, the plasma processing device can supply an RF signal, causing the periods of the pulse source RF signal and the pulse bias signal to be staggered. Furthermore, the plasma processing device can supply an RF signal such that the bias operation period continuously spans two cycles of the pulse source RF signal. Thus, the plasma processing device can precisely control the ion energy generated during plasma etching, thereby improving the performance of plasma etching. Additionally, by staggering the source operation period and the bias operation period, the plasma processing device can set a higher power level supplied during the rise of the pulse source RF signal (at the start of the cycle). Therefore, the plasma processing device can effectively achieve plasma etching.

[0194] As shown above, in the plasma processing apparatus of this embodiment, the source operating state can have at least two source power levels. Additionally, the bias operating state can have at least two bias power levels.

[0195] As shown above, in the plasma processing apparatus of this embodiment, the source operating state may have a first source power level and a second source power level following the first source power level. The bias operating state may have a first bias power level and a second bias power level following the first bias power level. The pulsed bias RF signal can transition to the bias operating state during the source-inactive period in each source cycle.

[0196] As shown above, in the plasma processing apparatus of the embodiment, the bias RF signal can be switched from a first bias power level to a second bias power level during the period when the source is not running in each source cycle.

[0197] As shown above, in the plasma processing apparatus of the embodiment, the transition from the first source power level to the second source power level in each source cycle can be substantially synchronized with the transition from the bias operating state to the bias non-operating state in each bias cycle.

[0198] As shown above, in the plasma processing apparatus of the embodiment, the first source power level can be greater than the second source power level.

[0199] As shown above, in the plasma processing apparatus of the embodiment, the first source power level may be lower than the second source power level.

[0200] As shown above, in the plasma processing apparatus of the embodiment, the second bias power level can be greater than the first bias power level.

[0201] As shown above, in the plasma processing apparatus of the embodiment, the second bias power level may be smaller than the first bias power level.

[0202] Furthermore, the plasma processing method described in this embodiment is a plasma processing method that can be used in a plasma processing apparatus. The plasma processing apparatus may include a plasma processing chamber, an antenna, a first RF generation unit, a substrate support unit, and a second RF generation unit. The antenna may be disposed above the plasma processing chamber. The first RF generation unit may be combined with the antenna to generate a first RF power. The substrate support unit may be disposed within the plasma processing chamber. The second RF generation unit may be combined with the substrate support unit to generate a second RF power. The plasma processing method may include the steps of supplying the first RF power to the antenna and supplying the second RF power to the substrate support unit during a first period. Additionally, 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 unit during a second period after the first period. Furthermore, 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 unit during a third period after the second period. Additionally, the plasma processing method may include the steps of supplying the second RF power to the substrate support unit without supplying RF power to the antenna during a fourth period after the third period. Then, the plasma processing method may repeatedly perform the above steps.

[0203] The embodiments disclosed in this specification are merely illustrative in all respects and should not be considered limiting. These embodiments may be omitted, substituted, and modified in various ways without departing from the scope and spirit of the present invention. For example, in the described embodiments, a plasma processing method implemented using an inductively coupled plasma device is used as an example; however, the technology of the present invention is not limited thereto, and can be applied to plasma processing methods using other plasma devices.

[0204] For example, instead of an inductively coupled plasma device, a capacitively coupled plasma (CCP) device can be used. In this case, the CCP device 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 then 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. Alternatively, the source RF generator 31a and the bias RF generator 31b may also be coupled to the lower electrode.

Claims

1. A plasma processing device, characterized in that, include: Plasma processing chamber; A substrate support portion disposed within the plasma processing chamber; Combined with the plasma processing chamber, a source RF generation unit generates pulsed source RF signals containing multiple source cycles. Each source cycle has a source operating state during a period of source operation and a source non-operation state during a period of source non-operation after the source operation period. and Combined with the substrate support, a bias RF generation unit generates a pulse bias RF signal. The pulse bias RF signal has multiple bias cycles with the same pulse frequency as the multiple source cycles. Each bias cycle has a bias operation state during a bias operation period and a bias non-operation state during a bias non-operation period after the bias operation period. The transition time to the bias running state in each bias loop is delayed relative to the transition time to the source running state in the corresponding source loop. The source non-running period overlaps with the bias non-running period, and the bias running period in each bias loop overlaps with the source running period in the next source loop. The source operating state has a first source power level and a second source power level following the first source power level. The bias operating state has a first bias power level and a second bias power level following the first bias power level. The pulse bias RF signal transitions to the bias operating state during the period when the source is not operating in each source cycle. The transition from the first source power level to the second source power level in each source cycle is substantially synchronous with the transition from the bias running state to the bias not running state in each bias cycle.

2. The plasma processing apparatus as described in claim 1, characterized in that: The pulsed bias RF signal transitions from the first bias power level to the second bias power level during the period when the source is not running in each source cycle.

3. The plasma processing apparatus as described in claim 1 or 2, characterized in that: The first source power level is greater than the second source power level.

4. The plasma processing apparatus as described in claim 1 or 2, characterized in that: The first source power level is lower than the second source power level.

5. The plasma processing apparatus as described in claim 1 or 2, characterized in that: The second bias power level is greater than the first bias power level.

6. The plasma processing apparatus as described in claim 1 or 2, characterized in that: The second bias power level is lower than the first bias power level.

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