JP2021182619A - Plasma processing method and plasma processing apparatus - Google Patents

Abstract

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

Description

The following disclosure relates to a plasma processing method and a plasma processing apparatus.

Patent Document 1 discloses a technique for pulsed an RF (Radio Frequency) signal in a device using an inductively coupled plasma (ICP, also called a Transformer Coupled Plasma (TCP)). Has been done. Patent Document 1 discloses, for example, synchronizing a source RF signal supplied to a coil and a bias RF signal supplied to a chuck so that the pulse sequences are reversed.

U.S. Patent Application Publication No. 2017/0040174

The present disclosure provides a technique capable of improving the processing performance of plasma etching.

The plasma processing apparatus according to one aspect of the present disclosure includes a plasma processing chamber, a substrate support unit, a source RF generation unit, and a bias RF generation unit. The substrate support is arranged in the plasma processing chamber. The source RF generator is coupled to the plasma processing chamber and configured to generate a pulse source RF signal containing multiple source cycles. Each source cycle has a source operating state during the source operating period and a source operating state during the source operating period after the source operating period. The bias RF generator is coupled to the substrate support and configured to generate a pulse bias RF signal. The pulse bias RF signal has multiple bias cycles having the same pulse frequency as multiple source cycles, and each bias cycle has a bias operating state during the bias operating period and a bias non-operating period after the bias operating period. Has a bias between non-operating states. The transition timing to the bias operating state in each bias cycle is delayed with respect to the transition timing to the source operating state in the corresponding source cycle. The source non-working period overlaps with the bias non-working period. The bias uptime in each bias cycle overlaps with the source uptime in the next source cycle.

According to the present disclosure, the processing performance of plasma etching can be improved.

FIG. 1 is a conceptual diagram of the configuration of the plasma processing apparatus according to the embodiment. FIG. 2 is a schematic vertical sectional view showing an example of the configuration of the plasma processing apparatus of FIG. FIG. 3 is a flowchart showing an example of the flow of plasma processing according to the embodiment. FIG. 4 is a diagram showing an example of a substrate processed by the plasma treatment according to the embodiment. FIG. 5 is a diagram showing an example of a waveform of an RF signal used for high frequency (RF) power supply in the plasma processing according to the embodiment. FIG. 6 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the waveform example 1 of the RF signal. FIG. 7 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the waveform example 2 of the RF signal. FIG. 8 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the waveform example 3 of the RF signal. FIG. 9 is a diagram for explaining changes in physical quantities in the plasma processing chamber according to the waveform example 4 of the RF signal. FIG. 10 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the first modification. FIG. 11 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modification 2. FIG. 12 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modification 3. FIG. 13 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modified example 4. FIG. 14 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modified example 5. FIG. 15 is a flowchart showing an example of the flow of RF power supply for plasma processing according to the embodiment. FIG. 16 is a flowchart showing another example of the flow of RF power supply for plasma processing according to the embodiment. FIG. 17 is a diagram for explaining an example of a shape abnormality that occurs in etching.

Hereinafter, embodiments for carrying out the plasma processing apparatus and plasma processing method according to the present disclosure (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings. The present disclosure is not limited to this embodiment. In addition, each embodiment can be appropriately combined as long as the processing contents do not contradict each other. Further, in each of the following embodiments, the same parts are designated by the same reference numerals, and duplicate explanations are omitted.

(Example of shape abnormality that occurs during etching)
First, an example of a shape abnormality that occurs in the etching of a silicon film will be described before the embodiment is described. FIG. 17 is a diagram for explaining an example of a shape abnormality that occurs in etching of a silicon film.

In recent years, in semiconductor manufacturing technology, a technique for processing a hole having a high aspect ratio has attracted attention. One example is High Aspect Ratio Contact (HARC). HARC is used for DRAM (Dynamic Random Access Memory) and 3D NAND. The aspect ratio of HARC used for DRAM is, for example, 45, and the aspect ratio of HARC used for three-dimensional NAND exceeds 65.

As the aspect ratio of the holes to be formed increases, it becomes difficult to form holes straight in the vertical direction. For example, as shown in FIG. 17 (A), a phenomenon of tapering occurs as it approaches the vicinity of the bottom of the hole. The cause of this phenomenon is considered to be, for example, that the incident direction of the ions in the plasma is slanted with respect to the depth direction of the pores, and it is difficult for the ions to be transported to the bottom of the pores. In addition, it is conceivable that the ions stay in the pores and obstruct the course of the following ions.

Further, as shown in FIG. 17B, a substance scraped by etching or a reaction product generated by plasma may be deposited on the substrate. When a substance is deposited near the opening of the hole, the opening of the hole is blocked and etching does not proceed. Further, even if the opening is not completely closed, it becomes difficult for ions to reach the inside of the hole, and the shape of the hole is distorted or etching does not proceed.

In addition, the edge portion of the opening of the mask may be scraped by etching. In this case, as shown in FIG. 17 (C), a phenomenon called Boeing may occur in which the incident direction of the ions with respect to the hole is distorted and the shape of the hole is distorted like a barrel at the side wall of the hole.

As described above, the processing performance of high aspect ratio plasma treatment depends on the radicals and ions generated in the plasma and the reaction products generated by the plasma treatment. Therefore, a technique capable of individually controlling the reaction species, radicals, by-products, etc. generated according to the progress of plasma treatment is desired.

(Embodiment)
In the embodiment described below, each physical quantity which is a parameter of plasma processing is controlled by applying RF (radio frequency) power used at the time of plasma generation in a pulse shape. The physical quantity to be controlled is, for example, ion energy, ion incident angle, radical flux, ion flux, amount of by-products, and the like.

The plasma processing apparatus according to the embodiment described below is an ICP apparatus. The control unit of the plasma processing apparatus of the embodiment controls the RF power (source RF signal, source power) supplied to the coil (antenna) by the control signal. In one embodiment, the supply of the source RF signal produces a high density plasma. The supply of RF power can be realized in various modes. For example, based on a program prepared in advance, the control unit of the plasma processing apparatus may switch the power supply path from the plurality of source RF generation units to sequentially supply source power of different power levels in a pulse shape.

The period in which RF power is supplied to the coil is called an on (operating) period, and the period in which RF power supply to the coil is stopped is called an off (non-operating) period. The source RF signal has a first state, for example, an on state (source on state) corresponding to an on period, and a second state, for example, an off state (source off state), which corresponds to an off period. The source RF signal is a pulse signal that forms one cycle (source cycle) between the on period of the first state and the off period of the second state following it. The frequency of the source RF signal may be, for example, from about 1 kHz to about 5 kHz.

The source RF signal of the embodiment may transition to two or more levels (for example, 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 is a first level at which a predetermined value of RF power is supplied to the coil and a second level at which RF power at a value lower than the first level is supplied to the coil. , May have. For example, the source RF signal may have a first level in which the coil is supplied with about 1000 watts of RF power and a second level in which the coil is supplied with about 250 watts of RF power. The RF power supplied at the second level may be about 100 watts or about 150 watts. The first and second levels may be high and low levels, respectively.

The control unit also controls the RF power (bias RF signal, bias power) supplied to the lower electrode of the plasma processing device by the control signal. In one embodiment, the supply of the bias RF signal causes ionic bonding in the substrate placed above the lower electrode, producing reaction species and radicals. The supply of RF power can be realized in various modes. For example, based on a program prepared in advance, the control unit of the plasma processing apparatus may switch the power supply path from the plurality of bias RF generation units to sequentially supply bias power of different power levels in a pulsed manner.

The period in which RF power is supplied to the lower electrode is called an on period, and the period in which RF power supply to the lower electrode is stopped is called an off period. The bias RF signal has a first state corresponding to an on period, for example, an on state (bias on state) and a second state corresponding to an off period, for example, an off state (bias off state). The bias RF signal is a continuous pulse signal that forms one cycle (bias cycle) between the on period of the first state and the off period of the second state following it. The frequency of the bias RF signal may be, for example, from about 1 kHz to about 5 kHz.

The bias RF signal of the embodiment may transition to two or more levels (for example, 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 is a first level in which a predetermined value of RF power is supplied to the lower electrode and a second level in which RF power having a value lower than the first level is supplied to the lower electrode. You may have a level and. For example, a bias RF signal may have a first level where the lower electrode is supplied with about 250 watts of RF power and a second level where the lower electrode is supplied with about 92.5 watts of RF power. good. The first and second levels may be high and low levels, respectively.

First, a configuration example of a plasma processing apparatus that executes plasma processing will be described.

(Configuration Example of Plasma Processing Device According to Embodiment)
FIG. 1 is a conceptual diagram of the configuration of the plasma processing apparatus according to the embodiment. FIG. 2 is a schematic vertical sectional view showing an example of the configuration of the plasma processing apparatus of FIG. The plasma processing apparatus 1 according to the embodiment will be described with reference to FIGS. 1 and 2. The plasma processing apparatus 1 shown in FIG. 2 is a so-called inductively-coupled plasma (ICP) apparatus, and generates inductively coupled plasma.

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 side wall 10b. The dielectric window 10a and the side wall 10b define the plasma processing space 10s in the plasma processing chamber 10. Further, the plasma processing apparatus 1 includes a support portion 11, an edge ring 12, a gas introduction portion 13 and an antenna 14 arranged in 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 arranged so as to surround the outer peripheral surface of the substrate support portion 11a. The antenna 14 is arranged above or above the plasma processing chamber 10 (dielectric window 10a).

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

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

The gas introduction unit 13 is configured to supply at least one processing gas from the gas supply unit 20 to the plasma processing space 10s. In one embodiment, the gas introduction unit 13 includes a central gas injection unit 13a and / or a side wall gas injection unit 13b. The central gas injection portion 13a is arranged above the substrate support portion 11a and is attached to the central opening formed in the dielectric window 10c. The side wall gas injection portion 13b is attached to a plurality of side wall openings formed on the side wall of the plasma processing chamber 10.

The gas supply unit 20 may include at least one gas source 21 and at least one flow rate controller 22. In one embodiment, the gas supply unit 20 is configured to supply one or more treated gases from the corresponding gas source 21 to the gas introduction unit via the corresponding flow rate controller 22. .. Each flow rate controller 22 may include, for example, a mass flow controller or a pressure-controlled flow rate controller. Further, the gas supply unit 20 may include one or more flow rate modulation devices that modulate or pulse the flow rate of one or more processing gases.

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 is configured to supply RF signals (RF power, for example, a source RF signal and a bias RF signal) to the lower electrode and the antenna 14. As a result, plasma is generated from at least one processing gas supplied to the plasma processing space 10s. In one embodiment, the RF signal is pulsed. The pulsed RF signal, pulsed RF power, pulsed source RF signal, and pulsed bias RF signal are examples of pulsed RF signals.

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 generator 31a is coupled to the antenna 14, and the bias RF generator 31b is coupled to the lower electrode in the substrate support 11a. The source RF generation unit 31a is configured to generate at least one source RF signal. In one embodiment, the source RF signal has frequencies 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 is configured to generate at least one bias RF signal. The bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. The generated bias RF signal is supplied to the lower electrode. Further, in various embodiments, the amplitude of at least one RF signal among the source RF signal and the bias RF signal may be pulsed or modulated. Amplitude modulation may include pulsing the RF signal amplitude between on and off states, or between two or more different on states.

Further, the power supply unit 30 may include a DC power supply unit 32. In one embodiment, the DC power supply unit 32 is configured to apply at least one DC voltage to the lower electrode. In one embodiment, at least one DC voltage may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the DC signal may be pulsed. Further, the DC power supply unit 32 may be provided in addition to the RF power supply unit 31 or may be provided in place of the bias RF generation unit 31b.

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

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

In one embodiment, the control unit (corresponding to the control device 50 in FIG. 2) processes computer executable instructions that cause the plasma processing device 1 to perform the various steps described in the present disclosure. The control unit may be configured to control each element of the plasma processing apparatus 1 to perform the various steps described herein. In one embodiment, a part or all of the control unit may be included in the plasma processing device 1. The control unit may include, for example, a computer. The computer may include, for example, a processing unit (CPU: Central Processing Unit), a storage unit, and a communication interface. The processing unit may be configured to perform various control operations based on the program stored in the storage unit. The storage unit may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

(Flow of plasma processing according to the embodiment)
FIG. 3 is a flowchart showing an example of the flow of plasma processing according to the embodiment. The plasma processing shown in FIG. 3 can be carried out 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 treatment according to the embodiment.

First, the substrate W is provided in the plasma processing chamber 10 (step S31). As shown in FIG. 4, for example, the substrate W includes a base layer L1 sequentially formed on a silicon substrate, an etching target layer (Si layer) L2, and a mask MK. A recess OP is formed in advance on the substrate W (see FIG. 4A). The recess OP may be formed in the plasma processing apparatus 1. Next, the plasma processing device 1 is controlled by the control unit, and the gas for etching is supplied from the gas supply unit 20 into the plasma processing chamber 10. Further, the plasma processing device 1 is controlled by the control unit to supply RF power from the RF power supply unit 31 (source RF generation unit 31a and bias RF generation unit 31b) to the lower electrode and the antenna 14 (coil). At this time, the RF power supply unit 31 supplies RF power at a level corresponding to the waveform of the RF signal to the lower electrode and the antenna 14. The waveform of the RF signal will be described later. By supplying RF power, plasma of the gas supplied into the plasma processing chamber 10 is generated, and plasma etching is executed (step S32). By plasma etching, the bottom of the recess OP formed in the mask MK of the substrate W is scraped, and the recess OP gradually becomes deeper (see (B) in FIG. 4). Then, the control unit of the plasma processing apparatus 1 determines whether or not a predetermined processing time has elapsed (step S33). After a predetermined processing time elapses, the bottom portion of the recess OP reaches the base layer L1 and has the shape shown in FIG. 4 (C). When it is determined that the processing time has not elapsed (step S33, No), the control unit returns to step S32 and continues plasma etching. On the other hand, when it is determined that the processing time has elapsed (step S33, Yes), the control unit ends the processing.

The plasma processing apparatus 1 according to the present embodiment supplies a source RF signal and a bias RF signal in the plasma etching in step S32. The plasma processing apparatus 1 controls the amount of ions and radicals in the plasma, the amount of by-products generated by plasma etching, and the like according to the waveforms of the source RF signal and the bias RF signal. Next, the waveforms of the source RF signal and the bias RF signal will be described.

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

The timing diagram shown in FIG. 5 100 illustrates the source power (the source RF signal) _{P S} and a bias power (bias RF signal) _{P B.} The source power _{P S,} is the RF power supplied from the source RF generator 31a to the antenna (coil) 14. The bias power P _B is RF power supplied from the bias RF generation unit 31b to the lower electrode in the substrate support portion 11a. Source RF generator unit 31a, for example, to generate the source power P _S in accordance with a control signal supplied from the control unit. Source power P _S generated is supplied to the coil. Bias RF generator 31b, for example, generates a bias power P _B in accordance with a control signal supplied from the control unit. The generated bias power P _S is supplied to the lower electrode.

In FIG. 5, period 150 indicates one period of the source RF signal. Period 160 indicates one period of the bias RF signal. In the following description, when it is not necessary to make a distinction, the cycles 150 ₁ , 150 ₂ , ... Are collectively referred to as the cycle 150, and the cycles 160 ₁ , 160 ₂ , ... Are collectively referred to as the cycle 160. One cycle refers to the period from the rising edge of the pulse signal to the next rising edge, that is, the total period of the on period and the off period. The source RF signal and the bias RF signal are pulse signals having the same frequency.

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

The bias RF signal repeats an on state (first state) in which RF power is supplied to the lower electrode and an off state (second state) in which RF power is not supplied to the lower electrode. In the example of FIG. 5, when the bias RF signal is on, the bias power P _B 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.

5, the rise of the bias RF signal is delayed by a period D ₁ with respect to the rise of the source RF signal. The bias RF signal rises while the source RF signal is in the off state after the source RF signal has transitioned from the on state to the off state. Thus, the timing at which the period of the source RF signal starts, the timing at which the period of the bias RF signal starts is shifted by the period D _1. In the example of FIG. 5, the transition timing from the bias OFF state _{(t 3)} in a previous bias cycle to the bias on state _P BL of the first bias cycle 160 _{1 (t 4)} corresponds to the first bias cycle 160 ₁ It is delayed with respect to the transition timing from the source-on state _PSH (0 to t ₁ ) in the first source cycle 150 _1. Further, as shown in t ₃ in FIG. 5, the source-off periods, overlap partially biased off period. Furthermore, as shown in t ₆ in FIG. 5, the bias on-period of the first bias cycle 160 ₁ overlaps the source ON period and partially in the second source cycle 150 _2.

Also, the lengths of the on and off periods of the source RF signal are different from the lengths of the on and off periods of the bias RF signal. In the example of FIG. 5, the duty ratio of the source RF signal (ratio of the length of the on period to one cycle) is about 40%. The duty ratio of the bias RF signal is about 60%. However, the duty ratios of the source RF signal and the bias RF signal are not limited to the above values. Further, the source RF signal and the bias RF signal may have the same duty ratio.

In this way, the source RF signal and the bias RF signal make state transitions separately. The timing of the state transition of the source RF signal and the power level of the transition source and the transition destination may be different from the timing of the state transition of the bias RF signal and the power level of the transition source and the transition destination.

_{Further, there is a period T OFF} in which neither the source RF signal nor the _{bias RF signal is supplied, and a period T ON in} which both the source RF signal and the bias RF signal are supplied. Supply mode of the source power P _S and a bias power P _B, the transition of the following five phases.

(1) First phase (ST _{1 in} FIG. 5):
The first phase is defined by _{the parameter set {PS1} , P _B1 , t _1}. Here, P _S1 is the value of the source power P _S supplied during the first phase. P _B1 is the value of the _{bias power P B} supplied during the first phase. t ₁ indicates the length of the period of the first phase. Here, the following relationship is established.
_PS1 > 0
P _B1 > 0
t ₁ > 0

In the first phase, the source power _{P S} with High power level _{P SH} (first source power level) is supplied to the coil, and a bias power _{P B} with High power level _{P BH} (second bias power level) It is supplied to the lower electrode. During the period t ₁ of the first phase, RF power is supplied to each of the upper and lower parts of the plasma processing apparatus 1 to generate plasma, and ions and radicals are generated in the plasma. At the time of the etching process, etching proceeds during the period t _1.

(2) Second phase (ST _{2 in} FIG. 5):
The second phase is defined by the parameter set _{{P S2, P B2, t} 2}. Here, P _S2 is the value of the source power P _S supplied during the second phase. P _B2 is the value of the _{bias power P B} supplied during the second phase. t ₂ indicates the length of the period of the second phase. Here, the following relationship is established.
_PS1 > _PS2 > 0
P _B1 = 0
t ₂ > 0

In the second phase, the source power _{P S} with Low power level _{P SL} (second source power level) is supplied to the coil, the supply of the bias power _{P B} is stopped. The second phase is, for example, the period t ₂ in FIG. Among period t _2, the RF power is supplied only to the upper portion of the plasma processing apparatus 1. Since RF power is not supplied to the lower electrode side, no force for drawing ions is generated on the lower electrode side. It also reduces the amount of ions and radicals produced.

(3) Third phase (ST _{3 in} Fig. 5):
The third phase is defined by the parameter set _{{P S3, P B3, t} 3}. Here, P _S3 is the value of the source power P _S fed into the third phase. P _B3 is the value of the _{bias power P B} supplied during the third phase. t ₃ indicates the length of the period of the third phase. Here, the following relationship is established.
P _S3 = P _B3 = 0
t ₃ > 0

In the third phase, the source power P _S and a bias power P _B together supply is stopped. The third phase is, for example, a period _{t 3} in FIG. During interval t _3, the plasma generation in the plasma processing apparatus 1 has a plasma processing space 10s is evacuated by the function of simultaneously pumping system 40 is stopped. At this time, the by-product (bi-product) generated by etching and staying at the bottom of the recess (FIG. 4, OP) is exhausted. The amount of ions and radicals in the plasma processing space 10s is also reduced.

(4) Fourth phase (ST _{4 in} Fig. 5):
The fourth phase is defined by the parameter set _{{P S4, P B4, t} 4}. Here, P _S4 is the value of the source power P _S supplied during the fourth phase. P _B4 is the value of the _{bias power P B} supplied during the fourth phase. t ₄ indicates the length of the period of the fourth phase. Here, the following relationship is established.
_PS4 = 0
P _B1 > P _B4 > 0
t ₄ > 0

In the fourth phase, _{the supply of the bias power P B} having the Low power level P _BL (first bias power level) is started while the supply _{of the source power P S is stopped.} Among duration t ₄ of the fourth phase, the source power P _S is not supplied, the plasma generation is not performed, the first to the ions generated in the second phase remains in the plasma processing space 10s in .. Thus, ions are drawn into the bottom of the recess (Fig. 4, OP) by the supply of the bias power P _B. In addition, the incident angle of the ions becomes closer to vertical, and the vertical etching of the side wall of the recess OP is promoted.

(5) Phase 5 (ST _{5 in} FIG. 5):
The fifth phase, the parameter set _{{P S5, P B5, t} 5} is defined by. Here, P _S5 is the value of the source power P _S fed into the fifth phase. P _B5 is the value of the _{bias power P B} supplied during the fifth phase. t ₅ indicates the length of the period of the fifth phase. Here, the following relationship is established.
_PS5 = 0
P _B1 = P _B5 > P _B4 > 0
t ₅ > 0

In the fifth phase, the supply of the source power _{P S} rises to High power level _{P BH} from the power level is Low power level _{P BL} of the bias power _{P B} remains stopped (transition). Therefore, as a preparatory step for the first phase, the ion energy in the plasma processing space 10s increases in the fifth phase. The amount of radicals and by-products remains reduced in the third phase.

After the fifth phase, it is again returned to the first phase, applying superimposed and the bias power P _B having a source power P _S and High power levels with High power level. Repeat such period, and applying a source power P _S starts first phase in the state that caused the ion energy to produce ions and radicals by previously applying a bias power P _B in the fifth phase. Therefore, the etching of the first phase can be promoted, and the ions can be efficiently drawn into the bottom of the recess OP. Further, etching can be further promoted by exhausting the by-product in the third phase.

As described above, by using the source RF signal and the bias RF signal having the pulse waveform of FIG. 5, vertical etching can be realized while controlling the states of ions, radicals and by-products in the plasma processing space 10s. Therefore, it is possible to suppress the shape abnormality generated by etching and improve the processing performance of plasma etching.

Incidentally, in the example of FIG. 5, the source power _{P S} when the on-state period _{t 1,} takes the value _{P SH,} when the subsequent on-state period _{t 2,} takes a value _{P SL.} Further, during the bias power _{P B} during the period _{t 4} takes the value _{P BL,} transitions in the subsequent period _{t 5} to the value _{P BH.} As described above, in the plasma processing method according to the embodiment, in order to control each physical quantity of plasma, the on state of the source RF signal may be controlled at two levels (three levels including the off state). Further, in the plasma processing method according to the embodiment, the on state of the bias RF signal may be controlled at two levels (three levels including the off state). In this way, by gradually changing the RF power value applied to each of the coil and the lower electrode, it is possible to finely adjust the parameters of plasma processing.

In the example of FIG. 5, the following relationship is established.
0 <P _SL <P _SH
0 <P _BL <P _BH
Frequency of source RF signal and bias RF signal: 0.1kHz to 5kHz
Duty ratio of source RF signal: Approximately 40%
Bias RF signal duty ratio: Approximately 60%
Length of P _SH period: Length of P _SL period = 1: 3
Length of P _BH period: Length of P _BL period = 1: 2
t ₁ : t ₂ : t ₃ : t ₄ : t ₅ = 1: 3: 1: 4: 1
However, this embodiment can be applied not only when the above relationship is established, but also in other relationships. Other relationships will be described later as modification examples.

6 to 9 are diagrams for explaining changes in physical quantities in the plasma processing chamber 10 according to an example of a waveform of an RF signal. With reference to FIGS. 6 to 9, changes in physical quantities according to the waveform of the RF signal will be described.

Waveform example 1 in FIG. 6 includes a “first phase” in which source power and bias power are supplied at the same time, a “second phase” in which only source power is supplied, and a “fourth phase” in which only bias power is supplied. Have. Compared to the waveform example of the above embodiment, the waveform example 1 does not have a "third phase" in which RF power is not supplied, and a "fifth phase" in which the power level of the bias power fluctuates before the rise of the source RF signal. The difference is that it does not have. In the case of waveform example 1, the ion flux, the radical flux, and the ion energy all increase in the first phase, and at the same time, the amount of by-products increases. After that, in the second phase, both amounts gradually decrease. When the supply of bias power is stopped, the ion energy becomes almost zero. In the fourth phase, the ion energy becomes larger than that in the first phase due to the supply of the bias power. On the other hand, the amounts of ion flux, radical flux and by-products have not changed significantly since the second phase.

The waveform example 2 of FIG. 7 is substantially the same as the waveform example 1 of FIG. However, the value of the bias power (P _BM ) of the fourth phase is larger than the value of the bias power (P _{BL) of the waveform example 1.} In the example of FIG. 7, the amounts of the ion flux, the radical flux, and the by-products are substantially the same as in the case of the waveform example 1 of FIG. However, the ion energy in the fourth phase is increased as compared with the waveform example 1 (C1 in FIG. 7). In addition, in FIG. 7 (C), on the same broken line as in FIG. 6 (C), the change in ion energy in the case of FIG. 7 (A) is shown by the thick broken line C1 only in the portion different from FIG. 6 (C). it's shown.

In the waveform example 3 of FIG. 8, the first phase is lengthened as compared with the waveform example 1 of FIG. 6, and the second phase is shortened by that amount. In the example of FIG. 8, the amounts of the ion flux and the radical flux are increased through the first and second phases as compared with the example of FIG. 6 (C2 and C3 in FIG. 8). On the other hand, there is no significant change in ion energy and the amount of by-products. Note that the thick broken lines C2 and C3 show only the parts different from FIG. 6 as in the case of C1.

The waveform example 4 of FIG. 9 is different from the waveform example 1 of FIG. 6 in that the fifth phase is provided. The power level of the fifth phase transitions _{from the power level P BL} of the fourth phase to P _BH. In the example of FIG. 9, the amounts of the ion flux, the radical flux, and the by-products are substantially the same as those of the waveform example 1 of FIG. The ion energy increases in the 5th phase in response to the switching of the bias power P _B in the 5th phase (C4 in FIG. 9). The thick broken line C4 in FIG. 9 shows only the portion different from (D) in FIG.

When etching is performed using the RF power of the waveform examples shown in FIGS. 6 to 9, in the waveform example 1 and the waveform example 3, the dimensions from the top to the bottom of the recess (the fluctuation of the critical dimension is shown in the waveform example 2). That is, when a slightly high level of bias power was applied as in the fourth phase of waveform example 2, it was possible to form holes having a more uniform size in the vertical direction during deep hole etching. When the ratio of the length of the first phase to the length of the second phase was changed as in Waveform Example 3, the wear of the mask was reduced, and the etching of the etching target film could be selectively realized. From this, it can be seen that the state of ions and radicals in the plasma processing space 10s, particularly in the vicinity of the substrate to be processed, changes according to the waveform of the RF power, which affects the performance of plasma processing. By adjusting the waveform of the RF signal, the performance of plasma processing, that is, the shape of the pattern formed by plasma processing can be controlled.

Note that the waveform examples 1 to 4 of FIGS. 6 to 9 do not include the third phase of the present embodiment, that is, the phase in which RF power is not supplied to either the coil or the lower electrode. By introducing the third phase in which RF power is not supplied, the amount of by-products in the plasma processing space 10s can be further reduced, and the etching accuracy in the vertical direction can be improved.

By the way, this embodiment is not limited to the waveform shown in FIG. 5, and the same effect can be obtained by a modified example. Modifications 1 to 5 will be described below with reference to FIGS. 10 to 14.

(Modification 1)
FIG. 10 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the first modification. The timing diagram shown in FIG. 10 200 shows the source power _{P S} and a bias power _{P B.} First, when the period t ₁ starts, the source power P _SH and the bias power P _BH are applied. Throughout the period t ₁ , the source power P _SH and the bias power P _BH are superimposed and applied at a constant level. Then comes a period _{t 3,} the supply both the source power _{P S} and a bias power _{P B} is stopped (period _{T OFF).} Next, when the period t ₄ is reached, the supply of the bias power P _{BH starts.} Then, the supply of the source power _{P SH} starts becomes the timing of the next cycle 150 _2, source power _{P SH} and bias power _{P BH} is applied to overlap (the period _T ON).

Unlike the waveform example of Fig. 5, the timing diagram 200 of FIG. 10, the second phase ie, supply to the coil of the source power P _S continues, there is no phase of stopping the supply of the bias power P _B. The timing diagram 200 of FIG. 10, the fifth phase that is, no phase level of the bias power P _B before the source power P _S supply changes. Therefore, the modification 1 can be applied in the case of pattern formation suitable for starting the exhaust of by-products (third phase) without adjusting the amount of ions and radicals. Further, the modification 1 can be applied even when it is not necessary to generate ion energy before plasma generation.

(Modification 2)
FIG. 11 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modification 2. In the timing diagram 210 shown in FIG. 11, _first , the source power _PSH and the bias power _PBH are applied in the period t1. In the next period _{t 2,} the level of the source power _{P S} is changed from _{P SH} to _{P SM.} Further, when the period t ₂ starts, the supply of the bias power P _{BH is stopped.} Next, the supply of the source power _{P SM} is stopped becomes a period _{t 3.} Therefore, in the period _{t 3,} none of the source power _{P S} and a bias power _{P B} is not supplied (period _{T OFF).} Then, when the period t ₄ is reached, the supply of the bias power _{PBM starts.} During the period _{t 4} is a bias power _{P B} level _{P BM} is supplied. Then, when the period t ₅ is reached, the level of the bias power P _B changes from P _{BM to P B H.} Then, while _{the supply of the bias power P BH} is continued, the source power P _SH is supplied when the next cycle 150 ₂ is reached, and the source power P _SH and the bias power P _BH are superposed and supplied (period _TON ). ..

Compared to the waveform example of Fig. 5, the second modification point level of the source power P _S is set to the P _SH and P _SM is different. Incidentally, the level of the source power _{P S,} the level _{P SH,} P _SM, are set to be from the high level to the low level in the order of _{P SL.} Further, the modification 2 is different from the waveform example of FIG. 5 in that the level of the _{bias power P B is set to P BH} and P _BM. The level of the bias power P _B is set from high level to low level in the order of _{levels P BH} , P _BM , and P _BL. For Modification 2, it is set in the ON state of the source power P _S and a bias power P _B into two levels. However, the lower level of the two levels is set to be a higher level than in the case of the example of FIG.

For example, if the before and after of the third phase for exhausting byproducts like to keep the electron density Ne, radical density Nr, the electron temperature Te, the ion energy εi such a high level, the source power P _S as in the modified example 2 And it is advisable to set a high level of a plurality of on states of the bias power P _B.

Also in the modification example 2, as with the waveform example of Fig. 5, the rise of the bias RF signal is delayed from the rising of the source RF signal by the period D _1. Moreover, the period _{T OFF} none of the source power _{P S} and a bias power _{P B} is not supplied there. Moreover, the period _{T ON} in which both the source power _{P S} and a bias power _{P B} is supplied there. The period _TON is the period from the timing at which the source RF signal rises to the timing at which the bias RF signal falls.

(Modification 3)
FIG. 12 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modification 3. In the timing diagram 220 shown in FIG. 12, _first , the source power _PSH and the bias power _PBM are supplied in the period t1. In a period _{t 2,} the level of the source power _{P S} is changed from _{P SH} to _{P SM.} Further, when the period t ₂ is reached, the supply of the bias power _{PBM is stopped.} Next, the supply of the source power _{P SM} is stopped becomes a period _{t 3.} Period between _{t 3,} both of the source power _{P S} and a bias power _{P B} is not supplied _{(T OFF).} Then, in the period t ₄ , the supply of the bias power P _{BH starts.} During the period _{t 4,} the bias power _{P B} level _{P BH} supplied. Then, when the period t ₅ is reached, the level of the bias power P _B changes from P _{BH to P BM.} Then, while _{the supply of the bias power P BM} is continued, when the cycle 150 ₂ starts, the source power P _SH is supplied, and the source power P _SH and the bias power P _BM are superposed and supplied (period _TON ).

Modification 3 is substantially the same as modification 2 of FIG. However, in the modified example 3, _{the transition order of the levels of the bias power P B} is different from that of the modified example 2. In Modification 2, the level between the bias power _{P B} of period _{t 1} is _{P BH,} during the period _{t 4} is _{P BM,} during the period _{t 5} is _{P BH.} On the other hand, in the modification 3, the level of the bias power P _{B during the period t 1 is P BM} , during the period t ₄ , it is P _BH , and during the period t ₅ , it is P _BM . In the second modification, _{the level of the bias power P B} changes in the order of high level, off state, low level, and high level from the first phase to the fifth phase. On the other hand, in the modified example 3, _{the level of the bias power P B} changes in the order of low level, off state, high level, and low level from the first phase to the fifth phase.

For example, in the case of plasma processing in which the ion energy is increased in the third phase and a large amount of ions are drawn into the bottom of the recess OP, the waveform of the modified example 3 is suitable.

(Modification example 4)
FIG. 13 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modified example 4. In the timing diagram 230 shown in FIG. 13, _first , the source power _PSM and the bias power _PBH are applied in the period t1. In a period _{t 2,} the level of the source power _{P S} is changed from _{P SM} to _{P SH.} Further, when the period t ₂ is reached, the supply of the bias power P _{BH is stopped.} Next, the supply of the source power _{P SH} is stopped in the period _{t 3.} Period between _{t 3,} both of the source power _{P S} and a bias power _{P B} is not supplied _{(T OFF).} Then, in the period _{t 4,} the supply of the bias power _{P BM} starts. During the period _{t 4,} the bias power _{P B} level _{P BM} is supplied. Then, when the period t ₅ is reached, the level of the bias power P _B changes from P _{BM to P B H.} Then, while the supply of the _{bias power P BH} is continued, the source power P _{SM is supplied when the period 150 2} is reached, and the source power P _SM and the bias power P _BH are superposed and supplied (period _TON ).

Modification 4 is substantially the same as modification 2 of FIG. However, the fourth modification, the transition order of the level of the source power P _S is different from the second modification. In Modification 2, the level between the source power _{P S} of the period _{t 1} is _{P SH,} a time period _{t 2} in _{P SM.} On the other hand, in the modification 3, the level of the bias power P _{B during the period t 1 is P SM} , and the level of the bias power P B is P _SH during the period t ₂ . In Modification 2, the level of the source power P _S is toward the third phase from the first phase, high, low, change in the order of off, no third phase toward fourth phase change. In Modification 4 In contrast, the level of the source power P _S is toward the third phase from the first phase, low, high, and changes in the order of off, no third phase toward fourth phase change.

Modification 4 is suitable for, for example, a treatment in which it is preferable to gradually increase the amounts of ions and radicals rather than rapidly increasing them in the first phase.

(Modification 5)
FIG. 14 is a diagram showing a waveform example of an RF signal used for RF power supply in the plasma processing according to the modified example 5. In the timing diagram 240 shown in FIG. 14, _first , the source power _PSM and the bias power _PBM are applied in the period t1. Then at time _{t 2,} the level of the source power _{P S} is changed from _{P SM} to _{P SH.} Further, when the period t ₂ is reached, the supply of the bias power _{PBM is stopped.} Next, the supply of the source power _{P SH} is stopped becomes a period _{t 3.} Period between _{t 3,} both of the source power _{P S} and a bias power _{P B} is not supplied _{(T OFF).} Then, when the period t ₄ is reached, the supply of the bias power P _{BH starts.} During the period _{t 4,} the bias power _{P B} level _{P BH} supplied. Then, when the period t ₅ is reached, the level of the bias power P _B changes from P _{BH to P BM.} Then, while the supply of the _{bias power P BM} is continued, the source power P _{SM is supplied when the period 150 2} is reached, and the source power P _SM and the bias power P _BM are superposed and supplied ( _TON ).

Modification 5, a bias power P _B of the third modification of FIG. 12 is a waveform that combines a source power P _S of the fourth modification of Fig. Bias power _{P B} of the third modification, the first phase toward the fifth phase, a low level (first phase), the off state (second and third phase), high level (fourth phase), low level (5 It changes in the order of phase). The source power P _S of the fourth modification, the first phase toward the fifth phase, a low level (first phase), a high level (second phase), the change in the order of OFF state (the third to fifth phase) do. Therefore, the waveform of the fifth modification, the first phase toward the fifth _{phase, {P S,} P _{B} is, {P SM, P BM}} {P SH, P BOFF}, {P SOFF, P BOFF} , {P _SOFF , P _BH } {P _SOFF , P _BM }. Here, when the on state includes only two levels in one waveform, one is referred to as a high level and the other is referred to as a low level, and is not referred to as a middle level for convenience. Moreover, the off-state of the source power _{P S P SOFF,} the off state of the bias power _{P B} indicated as _{P BOFF.}

Modification 5 is suitable for, for example, a treatment in which it is preferable to increase the ion energy once in the fourth phase, then decrease the ion energy, and then perform etching.

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

First, under the control of the control unit, the RF power supply unit 31 executes the RF power supply in the first phase (step S1510). The RF power supply of the first phase is defined by _{the processing parameters {PS1} , P _B1 , t _{1} of the first set.} Here, P _S1 > 0 and P _B1 > 0, t ₁ > 0.

Next, under the control of the control unit, the RF power supply unit 31 executes the RF power supply in the second phase (step S1520). RF power supply of the second phase is defined by the process parameters of the second set _{{P S2, P B2, t} 2}. Here, _PS2 > 0, P _B2 = 0, and t ₂ ≧ 0.

Next, under the control of the control unit, the RF power supply unit 31 executes the RF power supply in the third phase (step S1530). RF power supply of the third phase is defined by the process parameters of the third set _{{P S3, P B3, t} 3}. Here, P _S3 = 0 and P _B3 = 0, t ₃ > 0.

Next, under the control of the control unit, the RF power supply unit 31 executes the RF power supply in the fourth phase (step S1540). RF power supply of the fourth phase is defined by the process parameters of the fourth set _{{P S4, P B4, t} 4}. Here, P _S4 = 0 and P _B4 > 0, t ₄ > 0.

Next, under the control of the control unit, the RF power supply unit 31 executes the RF power supply in the fifth phase (step S1550). RF power supply of the fifth phase, the process parameters of the fifth set _{{P S5, P B5, t} 5} is defined by. Here, _PS5 = 0, P _B5 > 0, and t5 ≧ 0.

Steps S151 to S1540 are executed as one cycle. The cycle may be executed again after step S1540 and then back to step S1510.

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

First, under the control of the controller, RF power supply unit 31 supplies the source power P _S to the antenna (coil) 14, supplies a bias power P _B to the lower electrode at the same time. As a result, plasma is generated in the plasma processing space 10s. Further, the plasma contains ions and radicals (step S1610).

Then, under the control of the control unit, RF power supply unit 31 stops the supply of the bias power P _B to the lower electrode. Also, RF power supply unit 31 changes the value of the source power _{P S} is supplied to the antenna (coil) 14. RF power supply 31, for example, decrease or increase the source power _{P S.} As a result, the RF power supply unit 31 adjusts the amount of ions and radicals contained in the plasma in the plasma processing space 10s (step S1620).

Then, under the control of the control unit, RF power supply unit 31, in a state where the supply of the bias power P _B to the lower electrode is stopped to stop the supply of the source power P _S of the coil. Then, the amount of by-products in the plasma processing space 10s is reduced by the exhaust treatment of the plasma processing space 10s by the exhaust system 40 (step S1630).

Then, under the control of the control unit, RF power supply 31 supplies a bias power P _B to the lower electrode. The supply of the source power P _S remains stopped. A pulling force to the lower electrode by the bias power P _{B is generated (step S1640).}

Steps S161 to S1640 are executed as one cycle. The cycle may be executed again after step S1640 and then back to step S1610.

In addition, a part of the above-mentioned embodiment and modification may be changed as appropriate. The following are possible modifications.

(Other embodiments)
Source power _{P S} may be an alternating current (AC) power. The source power P _S is a high frequency (Radio Frequency: RF) even power, VHF may be (Very High Frequency) power. Source power _{P S,} for example, may be a RF power in the range of about 60MHz to about 200 MHz. The source power _{P S,} for example, may be a RF power in the range of about 25MHz to about 60 MHz. Source power _{P S,} for example, may be 27 MHz. In the present embodiment, the source power _{P S} generates inductively coupled plasma (ICP). Source power P _S, for example, plasma is generated by coupling the helical antenna.

The bias power P _B may be alternating current (AC) power. Further, the bias power P _B may be a direct current (DC) pulse power. The bias power P _B may be any one of RF (Radio Frequency) power, HF (High Frequency) power, and MF (Medium Frequency) power. The bias power P _B may be, for example, power with a frequency in the range of about 200 kHz to about 600 kHz. The bias power P _B may be, for example, 400 kHz. Further, the bias power P _B may be, for example, a power in the range of about 600 kHz to about 13 MHz.

Each source power P _S and a bias power P _B in each cycle may be applied as a single pulse or as a continuous pulse. For example, in the first phase, the source power P _S1 applied to the period t ₁ may be a single pulse, or may be a continuous pulse. Similarly, the bias power P _B2 applied during the period t ₂ may be a single pulse or a continuous pulse.

The duty ratios of the source RF signal and the bias RF signal can be set separately within the range of about 3% to about 90%.

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

Further, the duty ratio in the on state at the high level of the bias RF signal can be set in the range of about 5% to about 50%. Further, the duty ratio of the bias RF signal in the low level in the on state can be set in the range of 0% to about 45%. Further, the duty ratio in the off state of the bias RF signal can be set in the range of about 5% to about 90%.

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

Gas is supplied to the plasma processing chamber 10 at a flow rate selected according to a predetermined plasma processing. Gas is supplied to the plasma processing chamber 10 at substantially the same flow rate during one cycle including the first phase, the second phase, the third phase, the fourth phase and the fifth phase. The gas supplied contains, for example, hydrogen bromide (HBr). Further, the supplied gas includes, for example, a rare gas such as helium (He) or argon (Ar). The supplied gas is, for example, oxygen (O ₂ ), tetrafluoromethane (CF ₄ ), nitrogen trifluoride (NF ₃ ), sulfur hexafluoride (SF ₆ ), chlorine (Cl ₂ ), tetrachloromethane. (CCl ₄ ) and the like may be included.

The by-product produced during the plasma treatment according to the embodiment may be a compound containing the gas in the plasma treatment chamber 10 and one or more kinds of elements contained in the composition of the substrate. For example, when a silicon substrate and HBr gas are used, by-products containing SiBrx can be formed. In addition, silicon-containing residues such as silicon fluoride (SiFx) and silicon chloride (SiClx), fluorocarbon (CFx), fluorocarbon (CHxFy), etc. (in the case of treatment using a photoresist, an organic film, and a precursor), etc. Carbon-containing residues and the like can also be formed as by-products.

(Effect of embodiment)
As described above, the plasma processing apparatus according to the embodiment includes a plasma processing chamber, a substrate support unit, a source RF generation unit, and a bias RF generation unit. The substrate support is arranged in the plasma processing chamber. The source RF generator is coupled to the plasma processing chamber and configured to generate a pulse source RF signal containing multiple source cycles. Each source cycle has a source operating state during the source operating period and a source operating state during the source operating period after the source operating period. The bias RF generator is coupled to the substrate support and configured to generate a pulse bias RF signal. The pulse bias RF signal has a plurality of bias cycles having the same pulse frequency as the plurality of source cycles. Each bias cycle has a bias operating state during the bias operating period and a bias non-operating state during the bias non-operating period after the bias operating period. The transition timing to the bias operating state in each bias cycle is delayed with respect to the transition timing to the source operating state in the corresponding source cycle. The source-off period overlaps with the bias non-operation period. The bias uptime in each bias cycle overlaps with the source uptime in the next source cycle. In this way, the plasma processing device supplies the RF signal so that the periods of the pulse source RF signal and the pulse bias signal are deviated from each other. Further, the plasma processing apparatus supplies the RF signal so that the bias operation period lasts for two cycles of the pulse source RF signal. Therefore, the plasma processing apparatus can finely control the ion energy and the like generated during plasma etching to improve the plasma etching performance. Further, by shifting the source operating period and the bias operating period, the plasma processing apparatus can set a high power level to be supplied at the rising edge of the pulse source RF signal (at the start of the cycle). Therefore, the plasma processing apparatus can realize efficient plasma etching.

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

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

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

As described above, in the plasma processing apparatus according to the embodiment, the transition from the first source power level to the second source power level in each source cycle is the transition from the bias operating state to the bias non-operating state in each bias cycle. It may be substantially synchronized.

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

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

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

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

Further, the plasma processing method according to the above embodiment may be the plasma processing method used in the 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 located above the plasma processing chamber. The first RF generator may be coupled to the antenna to generate the first RF power. The substrate support may be located within the plasma processing chamber. The second RF generator may be coupled to the substrate support to generate the second RF power. The plasma processing method may include a step of supplying the first RF power to the antenna and supplying the second RF power to the substrate support portion in the first period. Further, the plasma processing method may include a step of supplying the first RF power to the antenna and stopping the supply of the second RF power to the substrate support portion in the second period after the first period. Further, the plasma processing method may include a step 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 portion in the third period after the second period. Further, the plasma processing method may include a step of supplying the second RF power to the substrate support portion in the fourth period after the third period without supplying the RF power to the antenna. Then, in the plasma processing method, each step may be repeatedly executed.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The above embodiments may be omitted, replaced or modified in various forms without departing from the scope of the appended claims and their gist. For example, in the above embodiment, the plasma processing method carried out by using an inductively coupled plasma apparatus has been described as an example, but the disclosed technique is not limited to this, and plasma treatment using another plasma apparatus is used. The disclosed technology can also be applied to the method. For example, a capacitively-coupled plasma (CCP) device may be used instead of the inductively coupled plasma device. In this case, the capacitively coupled plasma device includes two opposing electrodes located within the plasma processing chamber. In one embodiment, one electrode is located within the substrate support and the other electrode is located above the substrate support. In this case, one electrode functions as a lower electrode and the other electrode functions as an upper electrode. Then, the source RF generation unit 31a and the bias RF generation unit 31b are coupled to at least one of the two opposing electrodes. In one embodiment, the source RF generator 31a is coupled to the upper electrode and the bias RF generator 31b is coupled to the lower electrode. The source RF generation unit 31a and the bias RF generation unit 31b may be coupled to the lower electrode.

1 Plasma processing device 10 Plasma processing chamber 10a Dielectric window 10b Side wall 10s Plasma processing space 11 Support part 11a Board support part 11b Edge ring support part 12 Edge ring 13 Gas introduction part 13a Central gas injection part 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 Source RF generation unit 31b Bias RF generation unit 32 DC power supply unit 40 Exhaust system W board

Claims (10)

Plasma processing chamber and
A substrate support portion arranged in the plasma processing chamber and
A source RF generator coupled to the plasma processing chamber and configured to generate a pulsed source RF signal containing multiple source cycles, each source cycle being source operating during the source operating period and source operating. A source RF generator having a source inactive state during the source inactive period after the period,
A bias RF generator coupled to the substrate support and configured to generate a pulse bias RF signal, wherein the pulse bias RF signal has a plurality of bias cycles having the same pulse frequency as the plurality of source cycles. However, each bias cycle comprises a bias RF generator having a bias operating state during the bias operating period and a bias non-operating state during the bias non-operating period after the bias operating period.
The transition timing to the bias operating state in each bias cycle is delayed with respect to the transition timing to the source operating state in the corresponding source cycle, and the source operating period overlaps with the bias operating state, and each bias cycle The bias operating period in the plasma processing device overlaps with the source operating period in the next source cycle. The source operating state has at least two source power levels.
The bias operating state has at least two bias power levels.
The plasma processing apparatus according to claim 1. The source operating state has a first source power level and a second source power level after the first source power level.
The bias operating state has a first bias power level and a second bias power level after the first bias power level.
The plasma processing apparatus according to claim 2, wherein the pulse bias RF signal transitions to the bias operating state during the source non-operating period in each source cycle. The plasma processing apparatus according to claim 3, wherein the pulse bias RF signal transitions from the first bias power level to the second bias power level during the source non-operation period in each source cycle. Claim that the transition from the first source power level to the second source power level in each source cycle is substantially synchronized with the transition from the bias operating state to the bias not operating state in each bias cycle. 3 or the plasma processing apparatus according to claim 4. The plasma processing apparatus according to any one of claims 3 to 5, wherein the first source power level is larger than the second source power level. The plasma processing apparatus according to any one of claims 3 to 5, wherein the first source power level is smaller than the second source power level. The plasma processing apparatus according to any one of claims 3 to 7, wherein the second bias power level is larger than the first bias power level. The plasma processing apparatus according to any one of claims 3 to 7, wherein the second bias power level is smaller than the first bias power level. A plasma processing method used in a plasma processing apparatus, wherein the plasma processing apparatus is coupled to a plasma processing chamber, an antenna arranged above the plasma processing chamber, and the antenna to generate first RF power. The method comprises a 1RF generator, a substrate support disposed in the plasma processing chamber, and a second RF generator coupled to the substrate support to generate second RF power.
In the first period, a step of supplying the first RF power to the antenna and supplying the second RF power to the substrate support portion, and
In the second period after the first period, a step of supplying the first RF power to the antenna and stopping the supply of the second RF power to the substrate support portion.
In the third period after the second period, the step 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 portion.
In the fourth period after the third period, the step of supplying the second RF power to the substrate support portion without supplying the RF power to the antenna, and the step of supplying the second RF power to the substrate support portion.
Is repeated,
Plasma processing method.

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