Plasma processing device and power supply method

Abstract

The present invention provides a plasma processing device, comprising: a processing chamber; a carrier table, which is arranged in the processing chamber; a first electrode, which is arranged on the carrier table; a second electrode, which is arranged opposite to the first electrode; a first high-frequency power supply, which is connected to the first electrode; and a second high-frequency power supply, which is connected to the first electrode or the second electrode, wherein the first high-frequency power supply supplies a first pulse wave with a high level and a low level of a first high-frequency power or a waveform of a continuous wave of the first high-frequency power in a first period, supplies another waveform in a second period, and changes the low level of the first pulse wave in stages or continuously during the transition period; and the second high-frequency power supply supplies a second pulse wave with a high level and a low level of a second high-frequency power or a waveform of a continuous wave of the second high-frequency power in the first period, supplies another waveform in the second period, and changes the low level of the second pulse wave in stages or continuously during the transition period.

Description

Technical Field

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

[0002] For example, Patent Document 1 proposes applying a pulsed wave of high-frequency power for plasma generation and a pulsed wave of high-frequency power for offset voltage to a mounting table with a predetermined phase difference. In Patent Document 1, the duty cycle of the high-frequency power for plasma generation is controlled so that it is greater than the duty cycle of the high-frequency power for offset voltage.

[0003] <Prior Art Literature>

[0004] <Patent Document>

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

[0006] <Problems to be Solved by the Invention>

[0007] The present invention provides a plasma processing device and a power supply method capable of stabilizing plasma.

[0008] <Methods used to solve the problem>

[0009] According to one embodiment of the present invention, a plasma processing device is provided, comprising: a processing chamber; a carrier table, which is arranged in the processing chamber; a first electrode, which is arranged on the carrier table; a second electrode, which is arranged opposite to the first electrode; a first high-frequency power supply, which is connected to the first electrode; and a second high-frequency power supply, which is connected to the first electrode or the second electrode, wherein the first high-frequency power supply is constructed as follows: a first pulse wave with a high level and a low level or a first high-frequency power supply having a high level and a low level in the first period is supplied during a continuous first period, a second period, and a transition period between the first period and the second period. The second high-frequency power supply is constructed as follows: in the first period, a second pulse wave with a high level and a low level of the second high-frequency power or a waveform in the continuous wave of the second high-frequency power is supplied; in the second period, the second pulse wave and another waveform in the continuous wave of the second high-frequency power are supplied; and in the transition period, the low level of the first pulse wave is changed step by step or continuously.

[0010] <Effects of the Invention>

[0011] According to one aspect, a plasma processing device and a power supply method capable of stabilizing plasma are provided. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0013] Figure 2 A diagram for explaining a continuous wave and a pulse wave.

[0014] Figure 3 This is a diagram showing an example of transition from a continuous wave to a pulse wave in Reference Example 1.

[0015] Figure 4 This is a diagram showing an example of transition from a continuous wave to a pulse wave in Reference Example 2.

[0016] Figure 5 This is a diagram showing an example of transition from a continuous wave to a pulse wave according to one embodiment.

[0017] Figure 6 This is a diagram showing an example of a power supply method according to the embodiment.

[0018] Figure 7 It is a diagram for explaining the power supply method of the embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, the embodiment of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same components are given the same reference numerals, and repeated descriptions may be omitted.

[0020] [Plasma processing equipment]

[0021] use Figure 1 A plasma processing apparatus 10 according to one embodiment will be described. Figure 1 This is a schematic cross-sectional view of an example of a plasma processing apparatus 10 according to one embodiment. Plasma processing apparatus 10 includes a cylindrical processing chamber 11, which is made of aluminum or the like and has a hermetically sealed interior. Processing chamber 11 is connected to a ground potential. Inside processing chamber 11, a mounting table 12, made of aluminum or the like, is provided. Mounting table 12 is a cylindrical workbench for mounting a substrate W, such as a wafer, and serves as a lower electrode.

[0022] An exhaust passage 13 is formed between the sidewalls of the processing chamber 11 and the side surfaces of the mounting table 12, serving as a path for exhausting gas above the mounting table 12 out of the processing chamber 11. An exhaust plate 14 is positioned midway along the exhaust passage 13. Exhaust plate 14 is a plate-shaped member having numerous holes, functioning as a partition that divides the processing chamber 11 into upper and lower portions. The upper portion of the processing chamber 11, divided by exhaust plate 14, is a reaction chamber 17 for performing plasma processing. An exhaust device 38 is connected to an exhaust chamber (manifold) 18 in the lower portion of the processing chamber 11 via an exhaust pipe 15 and an APC (Adaptive Pressure Control) valve 16 for exhausting gas from the processing chamber 11. Exhaust plate 14 is used to capture or reflect plasma generated in the reaction chamber 17, preventing it from leaking into the exhaust chamber 18. The exhaust device 38 reduces the pressure within the processing chamber 11 by adjusting the APC valve 16, thereby maintaining a desired vacuum state.

[0023] The first high-frequency power supply 30 is connected to the mounting table 12 via a matching box 31. It supplies a first high-frequency power (hereinafter referred to as "LF" (Low Frequency)) for offsetting the frequency, for example, between approximately 400 kHz and 13.56 MHz, to the mounting table 12. The matching box 31 suppresses reflection of the high-frequency power and improves the efficiency of supplying the first high-frequency power LF for the offset voltage.

[0024] The second high-frequency power supply 19 is connected to the mounting table 12 via a matching box 20. It supplies a second high-frequency power (hereinafter referred to as "HF") for plasma excitation, for example, at a frequency of approximately 40 MHz, to the showerhead 29. The frequency of the second high-frequency power is higher than that of the first high-frequency power. The matching box 20 suppresses reflection of the high-frequency power and improves the efficiency of supplying the second high-frequency power HF for plasma excitation.

[0025] The mounting table 12 includes an electrostatic chuck 22 and a lower plate 12a. The electrostatic chuck 22 is positioned above the plate 12a. The plate 12a is formed from a conductive material such as aluminum. The electrostatic chuck 22 has a roughly disk-like shape and includes a layer of an insulator such as ceramic. The electrostatic chuck 22 further includes a chuck electrode 21 as an inner layer of the insulator layer. When a substrate W is mounted on the mounting table 12, the substrate W rests on the electrostatic chuck 22.

[0026] The chuck electrode 21 is connected to a DC power supply 23. When a DC voltage is applied to the chuck electrode 21, the substrate W is electrostatically attracted to the electrostatic chuck 22 by the Coulomb force or Johnson-Rahbek force generated thereby, and is thereby held.

[0027] On the mounting table 12 , an annular edge ring 24 (also called a focus ring) is mounted on a step formed on the outer periphery of the electrostatic chuck 22 so as to surround the periphery of the substrate W. The edge ring 24 is formed of, for example, silicon.

[0028] Inside the mounting table 12, for example, a circular refrigerant chamber 25 extending in the circumferential direction is provided. A low-temperature refrigerant, such as cooling water and / or Galden (registered trademark), is circulated in the refrigerant chamber 25 from a cooling unit via a refrigerant pipe 26. The mounting table 12, cooled by the low-temperature refrigerant, cools the substrate W and the edge ring 24 via the electrostatic chuck 22.

[0029] A plurality of heat transfer gas supply holes 27 are formed in the electrostatic chuck 22. A heat transfer gas, such as helium (He), is supplied to the heat transfer gas supply holes 27 via a heat transfer gas supply line 28. The heat transfer gas is supplied into the gap between the electrostatic chuck 22 and the substrate W through the heat transfer gas supply holes 27, thereby improving the heat transfer efficiency between the substrate W and the electrostatic chuck 22.

[0030] A showerhead 29 is disposed at the top of the processing chamber 11, facing the mounting table 12. The showerhead 29 functions as a gas supply mechanism and an upper electrode. The showerhead 29 includes an electrode plate 33 having a plurality of gas holes 32; a cooling plate 34 that detachably supports the electrode plate 33; and a cover 35 that covers the cooling plate 34. A buffer chamber 36 is provided inside the cooling plate 34. The buffer chamber 36 is connected to a gas inlet pipe 37. Gas is supplied from the gas supply source 8 to the showerhead 29 via the gas inlet pipe 37, and is then supplied to the reaction chamber 17 through the buffer chamber 36 and the plurality of gas holes 32.

[0031] In the reaction chamber 17 , plasma is generated by the gas supplied from the shower head 29 , and the plasma is used to perform plasma processing such as etching on the substrate W. Each element of the plasma processing apparatus 10 is controlled by a control unit 50 .

[0032] The control unit 50 includes a CPU 51 , a ROM (Read Only Memory) 52 , and a RAM (Random Access Memory) 53 , and controls desired processing such as etching processing according to a sequence set in a recipe stored in the RAM 53 and the like.

[0033] When performing etching processing in the plasma processing apparatus 10 of this configuration, a substrate W is first loaded into the processing chamber 11 by opening and closing the gate valve 9 and placed on the mounting table 12. A DC voltage is applied from the DC power supply 23 to the chuck electrode 21, thereby electrostatically attracting the substrate W to the electrostatic chuck 22. A desired gas output from the gas supply source 8 is introduced into the reaction chamber 17 through the showerhead 29 in a shower-like manner. Second high-frequency power HF for plasma excitation is applied from the second high-frequency power supply 19 to the mounting table 12. First high-frequency power LF for offset voltage is applied from the first high-frequency power supply 30 to the mounting table 12. Plasma is generated from the gas under the action of the high-frequency power, thereby subjecting the substrate W to plasma processing.

[0034] It should be noted that the lower plate 12a is an example of a first electrode disposed on the mounting table 12. The showerhead 29 is an example of a second electrode disposed opposite the first electrode. The first high-frequency power supply is connected to the first electrode. Similarly, the second high-frequency power supply is connected to the first electrode. However, the second high-frequency power supply may also be connected to the second electrode.

[0035] [Continuous wave / pulse wave of high-frequency power]

[0036] For the definition of high frequency power pulse wave, refer to Figure 2 Provide a brief explanation. Figure 2 A diagram for explaining a continuous wave and a pulse wave. Figure 2 The first high-frequency power LF and the second high-frequency power HF are collectively referred to as “high-frequency power RF”.

[0037] Figure 2 (a) shows the state where high frequency power RF is continuously applied. Figure 2 (a) shows a continuous wave of high-frequency power RF. Figure 2 (b) and (c) show the state where high frequency power RF is applied in a pulsed form. Figure 2 (b) and (c) show the pulse waves of high-frequency power RF.

[0038] exist Figure 2 In (b), the interval in which the high frequency power RF is controlled to be on (on interval) and the interval in which the high frequency power RF is controlled to be off (off interval) are repeated in each cycle T. Figure 2 In (c), within each cycle T, the interval (high interval) in which the high-frequency power RF is controlled to a high level H and the interval (low interval) in which the high-frequency power RF is controlled to a low level L are repeated.

[0039] The power level of the high-frequency power RF in the ON period can be the same as, higher than, or lower than the power level in the HIGH period. The power level of the high-frequency power RF in the OFF period is 0. The power level of the high-frequency power RF in the LOW period is lower than the power level in the ON period and includes 0 (OFF).

[0040] The power level of the high-frequency power RF in the high range can be the same as the power level of the continuous-wave high-frequency power RF, higher than the power level of the continuous-wave high-frequency power RF, or lower than the power level of the continuous-wave high-frequency power RF. The low-level high-frequency power RF applied in the low range has a lower power level than the continuous-wave high-frequency power RF.

[0041] In this embodiment, the high-level H high-frequency power RF in the high interval includes the high-frequency power RF of the power level in the on interval, and the low-level L high-frequency power RF in the low interval includes the high-frequency power RF of the power level (0) in the off interval. In the pulse wave high-frequency power RF, the time of the high interval (including the on interval) during which the high-level H high-frequency power RF is applied is set to TH, and the time of the low interval (including the off interval) during which the low-level L high-frequency power RF is applied is set to TL. The duty ratio is the ratio of the high interval time TH to the sum of the high interval time TH and the low interval time TL per cycle T, that is, it is expressed by TH / (TH+TL).

[0042] [Conversion from continuous wave to pulse wave of high-frequency power]

[0043] Next, refer to Figure 3 and Figure 4 The reference example of the present embodiment is used to describe a power supply method when the first high-frequency power and the second high-frequency power are converted from a continuous wave to a pulse wave or from a pulse wave to a continuous wave, and then the power supply method of the present embodiment is described.

[0044] (Reference Example 1)

[0045] Initially, refer to Figure 3 The method of transitioning from a continuous wave to a pulse wave in Reference Example 1 will be described. Figure 3 This diagram illustrates an example of the transition from a continuous wave to a pulse wave in Reference Example 1. In Reference Example 1, the transition from a continuous wave to a pulse wave for the first and second high-frequency powers is shown as (a) continuous wave (first period) → (b) pulse wave (transition period) → (c) pulse wave (second period). However, similar control can be achieved by transitioning from a pulse wave to a continuous wave in the order of (c) pulse wave (first period) → (b) pulse wave (transition period) → (a) continuous wave (second period).

[0046] In the following description and figures, the first high-frequency power is referred to as "LF" and the second high-frequency power is referred to as "HF." In Reference Example 1, the LF and HF are controlled synchronously. The LF and HF are repeatedly controlled identically within each cycle T. The first period, the second period, and the transition period between the first and second periods are continuous periods in the order of the first period, the transition period, and the second period.

[0047] In Reference Example 1, when applying LF and HF pulse waves, the timing of the on-time and the duty ratio are controlled to be the same. Specifically, the first high-frequency power supply 30 supplies a waveform of a high-level and low-level LF pulse wave (hereinafter referred to as the "first pulse wave") or a continuous wave of LF during the first period. Figure 3 In the example (a), a continuous wave of LF is applied in the first period.

[0048] Similarly, the second high frequency power source 19 supplies a waveform of a high level and a low level pulse wave (hereinafter referred to as a "second pulse wave") of HF or a continuous wave of HF in the first period. Figure 3 In the example (a), a continuous wave of HF is applied in the first period.

[0049] Next, the first high frequency power supply 30 supplies a first pulse wave of LF having a predetermined duty ratio of high level and low level during the transition period. Figure 3 In the example (b), the first pulse wave of Duty1 (LF pulse wave) is applied during the transition period. Duty1 of the first pulse wave is controlled to gradually decrease during the transition period, and the on-interval of LF gradually becomes shorter.

[0050] Similarly, the second high frequency power supply 19 supplies a second pulse wave of HF having a predetermined duty ratio of high level and low level during the transition period. Figure 3 In the example (b), the second pulse wave (HF pulse wave) of Duty 1 is applied during the transition period. Duty 1 of the second pulse wave is controlled to gradually decrease during the transition period, and the HF on-interval gradually shortens.

[0051] During the transition period, the LF duty ratio and the HF duty ratio are controlled to be the same, and the LF on-interval and the HF on-interval are synchronized. The LF duty ratio and the HF duty ratio are controlled so that they gradually decrease during the transition period until they reach the target duty ratio value. The target duty ratio value is set in advance and is Figure 3 Duty2 is shown in (c).

[0052] The first high frequency power supply 30 supplies the first pulse wave of LF in the second period so that the duty ratio becomes the target value. Figure 3 In the example of (c), the first pulse wave of LF having an on-time of Duty2 of a target value is applied in the second period.

[0053] Similarly, the second high frequency power supply 19 supplies the second HF pulse wave in a manner that the duty ratio becomes the target value during the second period. Figure 3 In the example of (c), the second pulse wave of HF having an on-time of Duty2 of a target value is applied in the second period.

[0054] (Reference Example 2)

[0055] In the power supply method shown in Reference Example 1, LF and HF are synchronized. In Reference Example 2 described below, LF and HF are not synchronized, but are offset by a predetermined time (see Figure 4 The control is performed by means of (b) offset). Figure 4 This is a diagram showing an example of transition from a continuous wave to a pulse wave in Reference Example 2.

[0056] In Reference Example 2, the timing of turning on the LF and HF pulses is staggered, and the duty ratios are controlled independently. Figure 4 In the first period shown in (a), the first high-frequency power supply 30 applies a continuous wave of LF, and the second high-frequency power supply 19 applies a continuous wave of HF in the first period.

[0057] Next, the first high frequency power supply 30 is Figure 4 The first pulse wave of Duty 1 is supplied during the transition period shown in (b). Similarly, the second high-frequency power supply 19 supplies the second pulse wave of Duty 1 during the transition period.

[0058] During the transition period, the LF duty ratio and the HF duty ratio are controlled to be the same, and the LF on-interval and the HF on-interval are not synchronized, but staggered by an offset. During the transition period, Duty1 is changed step by step or continuously. Figure 4 In the example (b), during the transition period, Duty1 is controlled so as to decrease in stages or continuously to reach the target value of the Duty ratio. The target value of the Duty ratio is set in advance and is Figure 4 Duty2 is shown in (c).

[0059] The first high frequency power source 30 supplies the first pulse wave of LF with a target value of Duty 2 during the second period. Similarly, the second high frequency power source 19 supplies the second pulse wave of HF with a target value of Duty 2 during the second period.

[0060] In Reference Example 2, the duty ratio is varied stepwise or continuously until it reaches the target value while the LF and HF transition from continuous wave to pulsed wave. This gradually changes the effective power of the LF and HF applied to the mounting table 12, reducing plasma fluctuations and stabilizing the plasma.

[0061] However, in Reference Example 2, the overlapping period of the LF and HF ON periods varies over time compared to Reference Example 1. Consequently, due to fluctuations in the plasma load, impedance matching becomes unstable, and the HF and LF power and Vpp (peak-to-peak voltage) become temporarily unstable. Consequently, the plasma becomes unstable.

[0062] In contrast, in the power supply method of one embodiment described below, the LF and HF power levels are varied stepwise or continuously during the low LF and low HF ranges. This reduces fluctuations in the plasma load and stabilizes the plasma.

[0063] (Implementation Method)

[0064] Reference Figure 5 The transition from a continuous wave to a pulse wave according to one embodiment will be described. Figure 5 This diagram illustrates an example of the transition from a continuous wave to a pulse wave in one embodiment. In this embodiment, the transition from a continuous wave to a pulse wave is shown as (a) continuous wave (first period) → (b) pulse wave (transition period) → (c) pulse wave (second period). However, the transition from a pulse wave to a continuous wave can also be similarly controlled by following the sequence: (c) pulse wave (first period) → (b) pulse wave (transition period) → (a) continuous wave (second period).

[0065] The LF and HF repeat the same control in each cycle T. The first period, the second period, and the transition period between the first and second periods are continuous periods. The LF on-interval and the HF on-interval are not synchronized, but are offset by an offset.

[0066] In this embodiment, the first high frequency power source 30 supplies a first pulse wave having a high level and a low level of LF or a continuous wave of LF in the first period. Figure 5 In the example (a), a continuous wave of LF is applied in the first period.

[0067] The first high frequency power supply 30 supplies the other waveform of the first pulse wave and the LF continuous wave in the second period. Figure 5 In the example of (c), the first pulse wave (LF pulse wave) is applied during the second period. Figure 5 In (b) and (c), the first pulse wave is controlled to have the desired duty ratio and does not fluctuate.

[0068] The first high frequency power source 30 changes the low level of the first pulse wave in stages or continuously during the transition period. Figure 5 In the example of (b), the low level of the first pulse wave indicated by "LF Low Duty" is gradually or continuously reduced during the transition period. At this time, the low level of the first pulse wave is gradually or continuously reduced until it becomes Figure 5 The high level of the first pulse wave indicated by "LF High Duty" is not changed during the transition period and the second period. The high level of the first pulse wave indicated by "LF High Duty" can be the same as Figure 5 The high-frequency power of the continuous wave of LF in (a) may be at the same power level or at different power levels.

[0069] Likewise, the second high frequency power source 19 supplies a second pulse wave of HF having a high level and a low level or a continuous wave of HF in the first period. Figure 5 In the example of (a), a continuous wave of HF is applied in the first period.

[0070] The second high frequency power supply 19 supplies the other waveform of the second pulse wave and the HF continuous wave in the second period. Figure 5 In the example of (c), the second pulse wave (HF pulse wave) is applied during the second period. Figure 5 In (b) and (c), the second pulse wave is controlled to the desired duty ratio and does not fluctuate.

[0071] The second high frequency power source 19 changes the low level of the second pulse wave in stages or continuously during the transition period. Figure 5 In the example of (b), the low level of the second pulse wave indicated by "HF Low Duty" is gradually or continuously reduced during the transition period. At this time, the low level of the second pulse wave is gradually or continuously reduced until it becomes Figure 5 The high level of the second pulse wave indicated by "HF High Duty" is not changed during the transition period and the second period. The high level of the first pulse wave indicated by "HF High Duty" can be the same as Figure 5 The high-frequency power of the HF continuous wave in (a) may be at the same power level or at different power levels.

[0072] In the power supply method of this embodiment, when the LF and HF are switched from continuous wave to pulse wave or from pulse wave to continuous wave, the duty ratio of HF and LF is not changed. Figure 5 In (b), the low-level HF and LF power in the low range within the dotted box B is changed in a step-by-step or continuous manner. Thus, by changing the effective LF and HF power supplied to the plasma load in a step-by-step or continuous manner, it is possible to switch from a continuous wave to a pulsed wave or vice versa without compromising the stability of the plasma load.

[0073] In particular, in this embodiment, the first and second pulse waves are offset by a predetermined phase difference, controlled so that the HF high-level interval (HF High Duty) and the LF high-level interval (LF High Duty) do not overlap, and the duty ratio is not changed. This allows for a transition from a continuous wave to a pulsed wave, or vice versa, while maintaining plasma stability. In this embodiment, while the HF high-level interval and the LF high-level interval are controlled so that they do not overlap, the HF high-level interval and the LF high-level interval may partially overlap. Furthermore, an offset need not be provided. Without an offset, by gradually or continuously varying the HF and LF low-level power, a transition from a continuous wave to a pulsed wave, or vice versa, can be achieved while maintaining plasma stability.

[0074] It should be noted that stepwise change means setting the LF low-level interval and the HF low-level interval to different values ​​in each cycle T, thereby gradually changing them. Continuous change means that in the LF low-level interval and the HF low-level interval, the LF and HF low-level powers are continuously changed within the same cycle T, and the LF and HF low-level powers are continuously changed in the low-level intervals of adjacent cycles T.

[0075] As an example of changing the low level of the first pulse wave in a stepwise or continuous manner, when the LF signal is a continuous wave during the first period and a pulse wave during the second period, the first high-frequency power source 30 can lower the low level of the first pulse wave to a predetermined target value (including turning it off). On the other hand, when the LF signal is a pulse wave during the first period and a continuous wave during the second period, the first high-frequency power source 30 can raise the low level of the first pulse wave to the high level of the first pulse wave or the level of the continuous wave signal during the transition period. In this case, the high level of the first pulse wave or the level of the continuous wave signal is the predetermined target value.

[0076] Similarly, when the HF power during the first period is a continuous wave and the HF power during the second period is a pulse wave, the second high-frequency power source 19 can lower the low level of the second pulse wave to a predetermined target value (including turning it off) during the transition period. On the other hand, when the HF power during the first period is a pulse wave and the HF power during the second period is a continuous wave, the second high-frequency power source 19 can raise the low level of the second pulse wave to the high level of the second pulse wave or the continuous wave level of the second high-frequency power during the transition period.

[0077] In addition, although the example of controlling two power levels, high or low, for LF and HF is shown, the present invention is not limited to this. For example, the present invention can also be applied to pulse waves having three or more power levels.

[0078] Moreover, in Figure 5 In this example, while the duty ratios for LF and HF are the same, they can be different. Furthermore, while the power supply method has been described for the transition period from a continuous wave to a pulse wave, and vice versa, this is not limiting. For example, the power supply method of this embodiment can also be applied to the transition from one pulse wave to another pulse wave.

[0079] [Example]

[0080] Last reference Figure 6 and Figure 7 An example of a power supply method according to the embodiment will be described. Figure 6 This is a diagram showing an example of a power supply method according to the embodiment. Figure 7 It is a diagram for explaining the power supply method of the embodiment. Figure 6 The processing is controlled by the control unit 50.

[0081] Figure 6 After the process shown in FIG. 1 is started, the control unit 50 controls HF and LF to be continuous waves in the first period (step S1). Figure 7 As shown in (a: First Period), during the first period, the HF and LF are controlled to continuous waves (CW). For example, the HF CW is controlled to 500W, and the LF CW is controlled to 200W. It should be noted that in this embodiment, the CW power level is controlled to be the same as the power level during the high-level interval of the pulse wave.

[0082] Next, the control unit 50 determines whether it is a transition period (step S2). When it becomes a transition period, the control unit 50 starts outputting the pulse wave of LF (first pulse wave) and the pulse wave of HF (second pulse wave) at a prescribed duty ratio and offset (step S3). Next, the control unit 50 outputs the pulse wave of HF and the pulse wave of LF while gradually changing the low level of the first pulse wave of LF and the low level of the second pulse wave of HF to a predetermined target value (step S4), thereby ending the present process. During the transition period, the low level of the first pulse wave and the low level of the second pulse wave can be gradually changed in a time period of less than 1 second. For example, in Figure 7 In the example of (b: transition period), the low level of the first pulse wave and the low level of the second pulse wave are changed stepwise at a cycle of 0.1 seconds during the transition period.

[0083] Therefore, if Figure 7 As shown in the frame C of (b), during the transition period, the voltage is gradually reduced at a constant time until it becomes Figure 7 By controlling the low level of the HF pulse wave in accordance with the target value of (c: second period), the fluctuation of the low level of the HF pulse wave (including the off state) can be changed gently.

[0084] Similarly, if Figure 7 As shown in the frame D of (b), during the transition period, the voltage is gradually reduced at a constant time until it becomes Figure 7 The low level of the LF pulse wave is controlled in accordance with the target value of (c). This allows the low level of the LF pulse wave (including disconnection) to change gently.

[0085] As described above, the power supply method and plasma processing apparatus 10 of this embodiment change the low levels of LF and HF in a stepwise or continuous manner during the transition from continuous wave to pulse wave or vice versa. This suppresses fluctuations in the plasma load and maintains plasma stability.

[0086] The power supply method and plasma processing apparatus 10 of the embodiments of this invention should be considered in all respects as illustrative and non-restrictive. The embodiments may be modified and improved in various forms without departing from the scope of the appended claims and the gist of the invention. The matters described in the various embodiments described above may be adopted in other configurations and combined within the scope of non-inconsistency.

[0087] The plasma processing apparatus of the present invention can be applied to any type of apparatus including Atomic Layer Deposition (ALD), Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

[0088] The plasma processing apparatus of the present invention may include three or more high-frequency power sources, and the power supply method of the present invention may be applied to power supply during the transition period between the three or more high-frequency power sources. Furthermore, the plasma processing apparatus of the present invention may include a high-frequency power source and a microwave source, and the power supply method of the present invention may be applied to power supply during the transition period between the high-frequency power source and the microwave source.

[0089] A plasma processing device may be any device that uses plasma to perform a predetermined process (e.g., film formation, etching, ashing, etc.) on a substrate. It is not limited to an etching device and may also be a film formation device, an ashing device, a doping device, etc.

Claims

1. A plasma processing device comprising: a processing chamber; A mounting table is disposed in the processing chamber; A first electrode is disposed on the mounting platform; a second electrode, disposed opposite to the first electrode; A first high-frequency power supply connected to the first electrode; and A second high-frequency power supply is connected to the first electrode or the second electrode. The first high frequency power supply is constructed as follows: In the continuous first period, the second period, and the transition period between the first period and the second period, one of the first pulse wave with high and low levels of the first high-frequency power supplied in the first period or the continuous wave of the first high-frequency power is selected. During the second period, the first pulse wave and the other waveform of the continuous wave of the first high-frequency power are supplied. During the transition period, the low level of the first pulse wave is changed stepwise or continuously. The second high frequency power supply is constructed as follows: During the first period, the second high-frequency power is supplied with a second pulse wave having a high level and a low level or a continuous wave of the second high-frequency power. During the second period, the second pulse wave and the other waveform of the continuous wave of the second high-frequency power are supplied. During the transition period, the low level of the second pulse wave is changed stepwise or continuously.

2. The plasma processing apparatus according to claim 1, wherein: When the continuous wave of the first high-frequency power and the continuous wave of the second high-frequency power are supplied during the first period, and the first pulse wave and the second pulse wave are supplied during the second period, the first high-frequency power source is configured to reduce the low level of the first pulse wave to a predetermined target value in a stepwise or continuous manner during the transition period. The second high-frequency power supply is configured to gradually or continuously reduce the low level of the second pulse wave to a predetermined target value during the transition period.

3. The plasma processing apparatus according to claim 1, wherein: When the first pulse wave and the second pulse wave are supplied during the first period, and the continuous wave of the first high-frequency power and the continuous wave of the second high-frequency power are supplied during the second period, the first high-frequency power source is configured to gradually or continuously increase the low level of the first pulse wave to the high level of the first pulse wave or the power level of the continuous wave of the first high-frequency power during the transition period. The second high-frequency power supply is configured to gradually or continuously increase the low level of the second pulse wave to the high level of the second pulse wave or the power level of the continuous wave of the second high-frequency power during the transition period.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein: The first pulse wave and the second pulse wave are shifted by a predetermined phase difference.

5. The plasma processing apparatus according to any one of claims 1 to 3, wherein: The first high-frequency power supply is configured to change the low level of the first pulse wave in stages within a time period of less than 1 second during the transition period. The second high-frequency power supply is configured to change the low level of the second pulse wave in stages within a time period of 1 second or less during the transition period.

6. The plasma processing apparatus according to any one of claims 1 to 3, wherein: The high-level section of the first high-frequency power does not overlap with the high-level section of the second high-frequency power.

7. A power supply method, performed by a plasma processing device, the plasma processing device comprising: A first electrode is disposed on a mounting table in a processing chamber; a second electrode is disposed opposite to the first electrode; a first high-frequency power supply is connected to the first electrode; a second high-frequency power supply is connected to the first electrode or the second electrode; and a control unit. The control unit is controlled in the following manner: During the first period of the continuous first and second periods and the transition period between the first and second periods, the first high-frequency power is supplied from the first high-frequency power source with a first pulse wave having a high level and a low level or a continuous wave of the first high-frequency power. During the second period, the first high-frequency power source supplies the other waveform of the first pulse wave and the first high-frequency power continuous wave. During the transition period, the low level of the first pulse wave is changed stepwise or continuously. During the first period, the second high-frequency power source supplies a second high-frequency power having a second pulse wave with a high level and a low level or a continuous wave of the second high-frequency power. During the second period, the second high-frequency power source supplies the other waveform of the second pulse wave and the second high-frequency power continuous wave. During the transition period, the low level of the second pulse wave is changed stepwise or continuously.

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