Processing method and plasma processing apparatus

Abstract

A processing method and a plasma processing apparatus that apply a pulsed wave of radio frequency power while maintaining plasma density are provided. The processing method uses a plasma processing apparatus having a first electrode and a second electrode, and includes a process of applying a pulsed wave of a first radio frequency power to either of the first electrode or the second electrode, and a process of applying a pulsed wave of a second radio frequency power having a frequency lower than the first radio frequency power to the first electrode with a given phase difference from the first radio frequency power, wherein different first and second on times of the second radio frequency power are controlled in such a manner that the on time of the second radio frequency power does not overlap with the on time of the first radio frequency power, and the first on time is controlled to be off immediately before the first radio frequency power is turned on.

Description

Technical Field

[0001] This disclosure relates to a processing method and a plasma processing apparatus. Background Technology

[0002] Patent Document 1 discloses a plasma processing method for plasma processing of a substrate on a mounting stage. The method applies a pulse wave of high-frequency power for plasma generation and a pulse wave of high-frequency power for bias with a frequency lower than that of the high-frequency power for plasma generation to the mounting stage. The high-frequency power pulse waves for plasma generation and bias are controlled such that they have a predetermined phase difference, and the duty cycle of the high-frequency power for plasma generation is controlled to be greater than or equal to the duty cycle of the high-frequency power for bias.

[0003] <Prior art documents>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-157735 Summary of the Invention

[0006] <Problem to be solved by this invention>

[0007] This disclosure provides a technique that can apply a pulsed wave of radio frequency power while maintaining plasma density.

[0008] <Methods for solving problems>

[0009] According to one embodiment of this disclosure, a processing method using a plasma processing apparatus having a first electrode and a second electrode is provided, comprising: applying a pulse wave of a first radio frequency power to either the first electrode or the second electrode; and applying a pulse wave of a second radio frequency power with a frequency lower than the first radio frequency power to the first electrode with a given phase difference between the second and first radio frequency powers, wherein different first and second on-times of the second radio frequency power are controlled in such a way that the on-time of the second radio frequency power does not overlap with the on-time of the first radio frequency power, and the first on-time is controlled to be off just before the first radio frequency power is about to be turned on.

[0010] <The Effects of the Invention>

[0011] According to one aspect, it is possible to apply a pulsed wave of radio frequency power while maintaining plasma density. Attached Figure Description

[0012] Figure 1This is a schematic cross-sectional view illustrating an example of a plasma processing system according to an embodiment.

[0013] Figure 2 This is a diagram used to illustrate radio frequency pulses.

[0014] Figure 3 This is a diagram illustrating an example of the application of a radio frequency pulse according to a comparative example.

[0015] Figure 4 This is a diagram illustrating an example of the application of a radio frequency pulse according to an embodiment.

[0016] Figure 5 This is a flowchart illustrating an example of a processing method according to an implementation method.

[0017] Figure 6 This is a diagram illustrating an example of alternative configuration items for performing a processing method according to an embodiment. Detailed Implementation

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same components, and repeated descriptions are sometimes omitted.

[0019] [Plasma Processing System]

[0020] use Figure 1 The plasma processing system 1 according to the embodiment will be described. Figure 1 This is a schematic cross-sectional view showing an example of a plasma processing system 1 according to an embodiment. In this embodiment, the plasma processing system 1 includes a plasma processing apparatus 1a and a control unit 1b. The plasma processing apparatus 1a includes a chamber 10, a gas supply unit 20, an RF (Radio Frequency) power supply unit 30, and an exhaust system 40. Additionally, the plasma processing apparatus 1a includes a support unit 11 and an upper electrode spray head 12. The support unit 11 is arranged in the lower region of the plasma processing space 10s within the chamber 10. The upper electrode spray head 12 is arranged above the support unit 11 and functions as part of the ceiling of the chamber 10.

[0021] The support portion 11 is configured to support the substrate W in the plasma processing space 10s. In an embodiment, the support portion 11 includes a lower electrode 111, an electrostatic chuck 112, and an edge ring 113. The electrostatic chuck 112 is disposed on the lower electrode 111 and is configured to support the substrate W on its upper surface. The edge ring 113 is disposed to surround the substrate W on the upper surface of the peripheral portion of the lower electrode 111. Additionally, although not shown in the figures, in an embodiment, the support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 112 and the substrate W 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 a heat transfer gas, flows in the flow path.

[0022] The upper electrode spray head 12 is configured to supply one or more processing gases from the gas supply unit 20 to the plasma processing space 10s. In one embodiment, the upper electrode spray head 12 has a gas inlet 12a, a gas diffusion chamber 12b, and a plurality of gas outlets 12c. The gas inlet 12a is in fluid communication with the gas supply unit 20 and the gas diffusion chamber 12b. The plurality of gas outlets 12c are in fluid communication with the gas diffusion chamber 12b and the plasma processing space 10s. In one embodiment, the upper electrode spray head 12 is configured to supply one or more processing gases from the gas inlet 12a to the plasma processing space 10s via the gas diffusion chamber 12b and the plurality of gas outlets 12c.

[0023] The gas supply unit 20 may include one or more gas sources 21 and one or more flow controllers 22. In an embodiment, the gas supply unit 20 is configured to supply one or more processing gases from their respective gas sources 21 to the gas inlet 12a via their respective flow controllers 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include one or more flow regulating devices for regulating or pulsed flow rates of the one or more processing gases.

[0024] The RF power supply unit 30 is configured to supply RF power to the lower electrode 111, the upper electrode spray head 12, or one or more electrodes such as both the lower electrode 111 and the upper electrode spray head 12, for example, one or more RF sources. Thus, plasma is generated from one or more processing gases supplied to the plasma processing space 10s. Therefore, the RF power supply unit 30 can function as at least a part of the plasma generation unit, which is configured to generate plasma from one or more processing gases in a chamber. In this embodiment, the RF power supply unit 30 includes a first RF source 30a and a second RF source 30b.

[0025] The first RF source 30a includes a first RF generation unit 31a and a first matching circuit 32a. In an embodiment, the first RF source 30a is configured to supply first RF power (hereinafter also referred to as "HF power") from the first RF generation unit 31a to the upper electrode spray head 12 via the first matching circuit 32a. For example, the first RF power may have a frequency in the range of 27MHz to 100MHz.

[0026] The second RF source 30b includes a second RF generation unit 31b and a second matching circuit 32b. In an embodiment, the second RF source 30b is configured to supply second RF power (hereinafter also referred to as "LF power") from the second RF generation unit 31b to the lower electrode 111 via the second matching circuit 32b. For example, the frequency of the second RF power is lower than the frequency of the first RF power, and the second RF power may have a frequency in the range of 400 kHz to 13.56 MHz.

[0027] The RF power supply unit 30 can be configured to supply a first RF power to the lower electrode 111 from the RF generation unit and a second RF power to the lower electrode 111 from other RF generation units. Alternatively, in other alternative embodiments, a DC voltage can be applied to the upper electrode spray head 12.

[0028] The exhaust system 40 may be connected, for example, to an exhaust port 10e located at the bottom of the 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.

[0029] In an embodiment, the control unit 1b processes computer-executable instructions for causing the plasma processing apparatus 1a to perform the various processes described herein. The control unit 1b may be configured to control various elements of the plasma processing apparatus 1a to perform the various processes described herein. In an embodiment, part or all of the control unit 1b may be included in the plasma processing apparatus 1a. The control unit 1b may, for example, include a computer 51. The computer 51 may include, for example, a processing unit (CPU, Central Processing Unit) 511, a storage unit 512, and a communication interface 513. The processing unit 511 may be configured to perform various control operations based on a program stored in the storage unit 512. The storage unit 512 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 513 may communicate with the plasma processing apparatus 1a via a communication line such as a LAN (Local Area Network).

[0030] [Pulse wave]

[0031] A brief explanation of the definition of RF power pulse waves is provided. Figure 2 This diagram illustrates the pulse wave of RF power. In the processing method according to the embodiment described later, a pulsed RF power is applied. In other words, both the first RF power (HF power) for plasma excitation and the second RF power (LF power) for ion attraction are pulsed. Hereinafter, the pulse wave of the first RF power is also referred to as an "HF pulse." The pulse wave of the second RF power is also referred to as an "LF pulse." The pulse wave of the RF power, collectively referred to as the first RF power and the second RF power, is also referred to as an "RF pulse."

[0032] like Figure 2 As shown, when an HF pulse is applied, the time during which the HF pulse is in the ON state (hereinafter also referred to as "ON time") is defined as "Ton". Conversely, the time during which the HF pulse is in the OFF state (hereinafter also referred to as "OFF time") is defined as "Toff". During the ON time Ton, an HF pulse with a frequency (Freq.) of 1 / (Ton+Toff) is applied.

[0033] When an LF pulse is applied, the on-time of the LF pulse is defined as "Ton". The off-time of the LF pulse is defined as "Toff". During the on-time Ton, an LF pulse with a frequency (Freq.) of 1 / (Ton+Toff) is applied.

[0034] The "duty" is represented by the ratio of the on time Ton to the total time of the on and off times (Ton+Toff), that is, it is represented by Ton / (Ton+Toff).

[0035] It should be noted that, in Figure 2 In this document, for the purpose of explaining the definition of a pulse wave, and for convenience, the on-time and off-time of the HF pulse and the LF pulse are shown with the same time and phase. However, in the processing method according to the embodiment described later, the on-time and off-time of the HF pulse and the LF pulse are not limited to being the same time. Furthermore, the HF pulse and the LF pulse have a given phase difference, the HF pulse is turned on once in one cycle, and the LF pulse is turned on more than twice in one cycle.

[0036] [Based on the application of the RF pulse in the comparative example]

[0037] Reference Figure 3 The method of applying the RF pulse according to the comparative example will be described. Figure 3 This is a diagram illustrating an example of the application of an RF pulse according to a comparative example. In Comparative Example 1 (a) and Comparative Example 2 (b), the HF power for plasma excitation and the LF power for ion attraction applied are pulsed HF pulses and LF pulses.

[0038] In Comparative Example 1 of (a), the frequency of both the HF pulse and the LF pulse is X (kHz), and the duration of one cycle is 1 / X (ms). In Comparative Example 1, the duty cycle of both the HF pulse and the LF pulse is Y%.

[0039] In Comparative Example 1 of (a), as shown by the applied timing, the timing and turn-on time for turning on the HF pulse and the LF pulse are the same and completely overlap, and are controlled to turn on the HF pulse and the LF pulse within a period of Y% of 1 / X (ms) of a cycle.

[0040] In Comparative Example 2 of (b), the difference from Comparative Example 1 of (a) is that there is a given phase difference between the LF pulse and the HF pulse, and the duty cycle of the LF pulse is Z%. In Comparative Example 2 of (b), the turn-on times of the HF pulse and the LF pulse do not overlap. The timing used to turn on the LF pulse is a timing offset by A% from the turn-on timing of the HF pulse.

[0041] An HF pulse is applied to the upper electrode spray head 12 to facilitate plasma generation and control the plasma density. An LF pulse is applied to the lower electrode 111 to control the ions in the generated plasma and attract the ions to the substrate W. However, an HF pulse can also be applied to the lower electrode 111 to facilitate plasma generation and control the plasma density.

[0042] like Figure 3 As shown in the application timing, in Comparative Example 1 (a), the high-order harmonic standing waves are generated because the on-times of the HF pulse and the LF pulse overlap. As a result, hot spots are generated on the substrate W, and it is sometimes difficult to perform uniform plasma treatment on the substrate.

[0043] In Comparative Example 2 of (b), plasma is generated from gas by applying an HF pulse, and then ions are controlled by applying an LF pulse to attract ions to the substrate W. Since the on-times of the HF pulse and the LF pulse do not overlap, hot spots on the substrate can be avoided, and uniform plasma treatment of the substrate can be achieved. Furthermore, in Comparative Example 2 of (b), by controlling the on-time of the LF pulse to a timing that compares with the on-time of the HF pulse, and by staggering the on-times of the HF pulse and the LF pulse, the ion energy distribution during plasma generation and the controllability of the ion incident angle on the substrate can be improved.

[0044] However, in Comparative Example 2 (b), plasma ignition was sometimes difficult, and it was sometimes impossible to maintain a suitable plasma density during the HF pulse on-time. In this case, it became difficult to perform uniform plasma treatment on the substrate W.

[0045] Therefore, in this embodiment, by coordinating the on-time of the HF pulse, the LF pulse is turned on just before the HF pulse is turned on, thereby promoting plasma ignition. The HF and LF pulses are applied while maintaining plasma density, and the ion energy distribution and the incident angle of the ions onto the substrate are controlled. Hereinafter, an embodiment of the application of the HF and LF pulses according to this embodiment will be described.

[0046] [Examples 1 and 2]

[0047] The following is for reference Figure 4 The application of the HF pulse and LF pulse according to the embodiment will be described. Figure 4 This is a diagram illustrating an example of the application of an RF pulse according to Embodiments 1 and 2.

[0048] In the settings of Example 1 of (a), the frequencies of both the HF pulse and the LF pulse are X (kHz), and the duration of one cycle is 1 / X (ms). In Example 1, the HF pulse is turned on once within one cycle, and the duty cycle (Duty) Y% for the on-time is set. The LF pulse is turned on twice within one cycle. The first on-time is the on-time immediately preceding the HF pulse (hereinafter referred to as the "first on-time"), and the duty cycle (Duty1) Z1% for the first on-time is set. The second on-time is the on-time following the HF pulse (hereinafter referred to as the "second on-time"), and the duty cycle (Duty2) Z2% for the second on-time is set. Furthermore, based on the timing of the HF pulse's on-time, an offset time A% is set in the positive direction from the reference to represent the timing of the LF pulse's on-time.

[0049] As shown in the timing application, in Example 1 of (a), control is performed in a manner that the on-time of the HF pulse does not overlap with the first and second on-times of the LF pulse. The HF pulse is controlled to be on during a period of Y% of one cycle, and the LF pulse is controlled to be staggered from the on-time of the HF pulse, and to be on in a non-overlapping manner with a given phase difference during periods of duty cycles Z1% and Z2%. Furthermore, the first on-time of the LF pulse is controlled to be off just before the HF pulse is about to be turned on. The second on-time of the LF pulse is controlled to be on after an offset of A% from the timing used to turn on the HF pulse.

[0050] like Figure 4 As shown in (b), the settings in Example 2 are the same as in Example 1. The difference is that in Example 1, the timing for turning off the first on-time of the LF pulse is consistent with the timing for turning on the HF pulse; in contrast, in Example 2 (b), the two timings are inconsistent. The difference from Example 1 is that the timing for turning off the first on-time of the LF pulse is shifted before the timing for turning on the HF pulse, that is, shifted forward within a range of less than 200 μs as indicated by Gap.

[0051] As described above, in Examples 1 and 2, the negative timing and first on-time for turning on the LF pulse, and the positive timing and second on-time for turning on the LF pulse are controlled based on the timing for turning on the HF pulse. It should be noted that the duty cycle Y% is an example of a first duty cycle used to turn on the first RF power. The offset time A% is an example of a given phase difference between the HF pulse and the LF pulse.

[0052] The LF pulse of the first on-time is used to ignite the plasma generated during the on-time of the HF pulse. In other words, by applying the LF pulse of the first on-time immediately before the timing for turning on the HF pulse, it is possible to reliably ignite the plasma and maintain the plasma density generated during the on-time of the HF pulse.

[0053] On the other hand, the reason for ensuring that the first turn-on time of the LF pulse does not overlap with the turn-on time of the HF pulse is as follows. Specifically, the second matching circuit 32b monitors approximately 10% of the latter half of the LF pulse's turn-on time and performs impedance adjustment. This is because, since a reflected wave of LF power from the plasma side is generated during the rise of the LF pulse, adjusting based on approximately 10% of the latter half of the LF pulse's turn-on time, which generates almost no reflected wave, improves the accuracy of impedance adjustment.

[0054] If a portion of the latter 10% of the on-time of the LF pulse used for impedance adjustment overlaps with the on-time of the HF pulse, the HF power will affect the impedance adjustment even if impedance adjustment is intended to be based solely on the LF power. Therefore, the second matching circuit 32b cannot perform precise impedance adjustment. Consequently, the first on-time of the LF pulse is controlled to be turned off immediately before the on-time of the HF pulse. It should be noted that the timing for turning off the first on-time of the LF pulse is limited to a range of 0–200 μS or less relative to the timing for turning on the HF pulse.

[0055] It should be noted that by applying the LF pulse in a manner that the second turn-on time of the LF pulse does not overlap with the turn-on time of the HF pulse, the ion energy distribution during plasma generation and the controllability of the ion incident angle on the substrate can be improved.

[0056] [Solution]

[0057] After setting the above-mentioned settings in advance, the processing method according to the implementation method is executed. (Refer to...) Figure 5 The processing method according to the implementation method will be described. Figure 5 This is a flowchart illustrating an example of a processing method according to an implementation method.

[0058] When this process begins, the control unit 1b of the plasma processing apparatus 1a turns on the LF pulse during a period of duty cycle (Duty1) Z1% in the negative direction prior to the HF pulse turn-on timing (step S1). Thus, the first turn-on time of the LF pulse is controlled.

[0059] Next, the control unit 1b turns off the LF pulse and turns on the HF pulse during the duty cycle Y%, and starts counting the offset time (step S2).

[0060] Next, control unit 1b turns off the HF pulse (step S3). Then, control unit 1b determines whether the offset time A% has elapsed (step S4). When the offset time A% has elapsed, control unit 1b turns on the LF pulse for a period of duty cycle (Duty2) Z2% (step S5). Thus, the second on-time of the LF pulse is controlled. Next, control unit 1b turns off the LF pulse (step S6).

[0061] Next, the control unit 1b determines whether it is the next cycle (step S7). When the time reaches Z1% of the duty cycle (Duty1) in the negative direction from the reference for the timing of the HF pulse being turned on, it is determined that it is the next cycle, and the process returns to step S1, turning on the LF pulse during the Z1% duty cycle (Duty1). By repeating the processing of steps S1 to S7 for each cycle, the application of the HF pulse and the LF pulse can be controlled in a way that prevents the HF pulse and the LF pulse from overlapping.

[0062] That is, by applying an LF pulse with a first on-time immediately preceding the HF pulse, plasma ignition can be reliably achieved, and the plasma density generated during the on-time of the subsequent HF pulse can be maintained. Furthermore, by controlling the first on-time of the LF pulse to prevent overlap with the on-time of the HF pulse, the accuracy of impedance adjustment can be improved. Additionally, by controlling the second on-time of the LF pulse to prevent overlap with the on-time of the HF pulse independently of the first on-time, the controllability of ion energy distribution and the incident angle of ions onto the substrate can be improved.

[0063] [Alternative Settings]

[0064] Reference Figure 6 Alternative settings for performing the processing method according to the implementation method will be described. Figure 6 This is a diagram illustrating alternative configuration items for performing the processing method according to the embodiment.

[0065] exist Figure 6 In alternative setting item 1 of (a), the duty cycle Y% used to represent the on-time of the HF pulse is set. Based on the timing of the HF pulse's on-time, an offset time A% used to represent the timing of the LF pulse's on-time is set in the positive direction from the reference.

[0066] As a setting item for controlling the first and second on-times of the LF pulse from offset time A% to the next cycle, the off-time (Duty Off) W% of the LF pulse during the period from offset time A% to the next cycle, and the start timing T of the off-time W% are set instead of setting the duty cycle (Duty1, Duty2) of each on-time.

[0067] Therefore, as shown by the applied timing, the off-time of the LF pulse is divided into the first on-time and the second on-time. Furthermore, the timing used for this division can be controlled by the start timing T of the off-time.

[0068] It should be noted that the frequency of both the HF and LF pulses is X (kHz). The duty cycle Y% is an example of the first duty cycle used to turn on the first RF power. The offset time A% is an example of a given phase difference between the HF and LF pulses.

[0069] By setting the above parameters, control of the LF pulse turn-on timing, with the premise of improving plasma ignition during HF pulse turn-on, is achieved. Specifically, firstly, control unit 1b turns on the HF pulse with a duty cycle Y%. Next, control unit 1b turns on the LF pulse after an offset time A% has elapsed since the HF pulse turn-on timing, thereby controlling the second turn-on time. Then, control unit 1b turns off the LF pulse during a turn-off time W% from the start timing T of the turn-off time, and then turns on the LF pulse until the turn-on timing of the next HF pulse cycle, thereby controlling the first turn-on time.

[0070] As described above, in the control performed by alternative setting item 1, the off-time W% of the LF pulse, its start timing T, and the offset time A% are set. Furthermore, after the LF pulse is turned on based on the offset time A%, the off-time of the LF pulse is controlled by the off-time W% of the LF pulse and its start timing T, thereby enabling the determination of the first turn-on time and the second turn-on time.

[0071] This alternative setting 1 is in Figure 4 The reference setting item shown includes a method for setting the turn-off timing, and the techniques of Examples 1 and 2 can be used. However, the premise is that the LF pulse is turned on until the turn-on timing of the next cycle of the HF pulse is reached, based on the offset time A%.

[0072] exist Figure 6In alternative setting item 2 of (b), the duty cycle (Duty) Y% for representing the on-time of the HF pulse and the duty cycle (Duty) Z% including the first and second on-times of the LF pulse are set. An offset time A for representing the on-time of the LF pulse is set from the timing of the on-time of the HF pulse.

[0073] It should be noted that the frequency of both the HF and LF pulses is X (kHz). The duty cycle Y% is an example of the first duty cycle used to turn on the first RF power. The offset time A% is an example of a given phase difference between the HF and LF pulses.

[0074] In Alternative Setting Item 2, since control for turning off the LF pulse is performed during the HF pulse's on-time, it is not necessary to set the LF pulse's off-time W% and start timing T as set in Alternative Setting Item 1. However, in Alternative Setting Item 2, the duty cycle Z% is set based on the on-time of the LF pulse after the offset time A%.

[0075] By setting the above parameters, control of the LF pulse turn-on timing, with the premise of improving plasma ignition during HF pulse turn-on, is achieved. Specifically, firstly, control unit 1b turns on the HF pulse with a duty cycle Y%. Next, control unit 1b turns on the LF pulse after an offset time A% has elapsed since the HF pulse turn-on timing, thereby controlling the first turn-on time. Then, control unit 1b turns off the LF pulse during the HF pulse turn-on time and turns on the LF pulse at the HF pulse turn-off timing to control the second turn-on time.

[0076] As described above, in control performed using alternative setting item 2, compared to the setting items in Examples 1 and 2 and alternative setting item 1, the setting item can be suppressed, thus making control easier to execute. Furthermore, by periodically adjusting the duty cycle of the HF pulse (Duty Ramp), overlap between the HF pulse and the LF pulse can be prevented.

[0077] As described above, by means of the processing method and plasma processing apparatus according to the embodiments, it is possible to apply a pulse wave of RF power while maintaining plasma density.

[0078] It should be considered that the processing methods and plasma processing apparatus according to the embodiments disclosed herein are exemplary in all respects and not restrictive. Various modifications and improvements can be made to the above embodiments without departing from the appended claims and their spirit. Other structures and combinations may be used for the content described in the above embodiments without contradiction.

[0079] For example, although the LF pulse is controlled by dividing it into a first on-time and a second on-time within one cycle, the LF pulse is not limited to this. In addition to the first on-time of Duty 1 and the second on-time of Duty 2 as in Examples 1 and 2, it can also have a third on-time of Duty 3 or more on-times. In this case, it is possible to... Figure 4 After the second turn-on time of Duty2 shown, there is a third turn-on time of Duty3 or more different turn-on times.

[0080] The plasma processing apparatus disclosed herein can be applied to any type of apparatus, including atomic layer deposition (ALD) apparatus, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna (RLSA), electron cyclotron resonance plasma (ECR), and helicon wave plasma (HWP).

[0081] In addition, the plasma processing apparatus can be any apparatus that performs a predetermined treatment on the substrate (such as film formation, etching, etc.), and is not limited to a plasma processing apparatus.

Claims

1. A processing method using a plasma processing apparatus having a first electrode and a second electrode, comprising: The process of applying a pulse wave of first radio frequency power to either the first electrode or the second electrode; as well as The process of applying a pulse wave of a second radio frequency power to the first electrode with a given phase difference from the first radio frequency power, wherein the frequency of the second radio frequency power is lower than the frequency of the first radio frequency power. Specifically, the different first and second on-times of the pulse wave of the second radio frequency power are controlled in a manner that prevents the on-time of the pulse wave of the second radio frequency power from overlapping with that of the pulse wave of the first radio frequency power. Just before the pulse wave of the first radio frequency power is about to be turned on, the first turn-on time is controlled to be off.

2. The processing method according to claim 1, wherein, Within a range of 0 to 200 μS before the pulse wave that is about to turn on the first radio frequency power, the first turn-on time is turned off.

3. The processing method according to claim 1 or 2, further comprising: The process of setting a first duty cycle for controlling the on-time of the pulse wave of the first radio frequency power, the given phase difference, an off-time for dividing the first on-time and the second on-time of the pulse wave of the second radio frequency power, and the start timing of the off-time. Specifically, the pulse wave of the first radio frequency power is switched on with the first duty cycle. The second turn-on time of the pulse wave of the second radio frequency power is controlled by the given phase difference, and after the pulse wave of the second radio frequency power is turned off at the turn-off time starting from the start timing of the turn-off time, the pulse wave of the second radio frequency power is turned on to control the first turn-on time.

4. The processing method according to claim 1 or 2, further comprising: The process of setting a first duty cycle for controlling the on-time of the pulse wave for the first radio frequency power, and the given phase difference. Specifically, the pulse wave of the first radio frequency power is switched on with the first duty cycle. The first turn-on time of the pulse wave of the second radio frequency power is controlled by the given phase difference, the pulse wave of the second radio frequency power is turned off at a timing for turning on the pulse wave of the first radio frequency power, and the pulse wave of the second radio frequency power is turned on at a timing for turning off the pulse wave of the first radio frequency power to control the second turn-on time.

5. The processing method according to claim 1 or 2, wherein, The pulse wave of the second radio frequency power during the first on-time is used to ignite the plasma generated during the on-time of the pulse wave of the first radio frequency power.

6. A plasma processing apparatus, comprising a first radio frequency source, a second radio frequency source, a first electrode, a second electrode, and a control unit. in, The control unit A pulse wave of first radio frequency power is applied from the first radio frequency source to either the first electrode or the second electrode. A pulse wave of a second radio frequency power is applied to the first electrode from the second radio frequency source with a given phase difference from the first radio frequency power, wherein the frequency of the second radio frequency power is lower than the frequency of the first radio frequency power. To ensure that the turn-on time of the second radio frequency power pulse wave does not overlap with the turn-on time of the first radio frequency power pulse wave, different first and second turn-on times of the second radio frequency power pulse wave are controlled, and Just before the pulse wave of the first radio frequency power is about to be turned on, the first turn-on time is controlled to be off.

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