Plasma processing apparatus

Abstract

A plasma processing apparatus includes: a processing chamber for performing plasma processing on a sample; a first high-frequency power supply for supplying a first high-frequency power for generating plasma; a sample stage for placing the sample; and a second high-frequency power supply for supplying a second high-frequency power to the sample stage. In this plasma processing apparatus, it further includes: a control device that, when modulating the first high-frequency power by a first waveform having a first period and a second period adjacent to the first period, and modulating the second high-frequency power by a second waveform having a period A and a period B, controls the second high-frequency power supply so as to supply each of the second high-frequency powers of the period A during the first period and the second period, the amplitude of the second period being smaller than the amplitude of the first period and greater than 0, and the amplitude of the period A being greater than the amplitude of the period B.

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus. Background Art

[0002] In a plasma etching apparatus of an electron cyclotron resonance (ECR) type, RF (Radio Frequency) high-frequency power is used to accelerate ions incident on a semiconductor element.

[0003] In recent years, with the increase in the integration degree of semiconductor devices, it has been required to achieve both shape controllability during etching and in-plane uniformity of the wafer surface. As one of the techniques for realizing high-precision plasma etching, Patent Document 1 discloses a plasma etching method in which the magnitude of the energy supplied to a plasma formation unit is adjusted so that a plasma is periodically formed in a strong plasma state, a weak plasma state, or a plasma disappearance state.

[0004] In addition, Patent Document 2 discloses a technique in which a synchronous RF bias power is applied to a source power supply (microwave) that has been time-modulated, and an RF bias power obtained by phase-modulating the time-modulated microwave is applied.

[0005] Furthermore, there is also a technique in which a source power supply for plasma generation can be pulse-applied not only in two states of pulse enable (ON) / cutoff (OFF), but also in three (or more) intervals of pulse high / pulse low / cutoff. Patent Document 3 discloses a method in which a pattern vertical etching with a density difference is achieved by applying an RF bias power in a pulse low interval.

[0006] Furthermore, Patent Document 4 discloses a method in which an etching that can make the etching rate distribution uniform and can suppress isotropic etching is achieved by setting the microwave output value to an output value of two or more in a pulse enable interval.

[0007] In all of these prior arts, the source power supply for generating a plasma is pulsed to achieve low-density plasma and low-dissociation etching, and an RF bias power is applied in consideration of plasma species / plasma density to attract an appropriate amount of ions and ion energy to the wafer, thereby achieving an etching shape, a selectivity ratio, and in-plane uniformity of the wafer surface.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: JP-A-59-47733

[0011] Patent Document 2: JP-A-2015-115564

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 2017-69542

[0013] Patent Document 4: Japanese Patent Application Laid-Open No. 2020-17565 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] However, although etching under low dissociation can be achieved by applying a pulsed source power for plasma generation, there are various problems in the prior art.

[0016] For example, when only the source power is pulsed and the RF bias power is a continuous wave, the RF bias power cannot be applied when the plasma goes out. In response to this, if the cut-off period of the pulsed source power is limited to be short and the pulse repetition frequency is increased to prevent the plasma from going out, there is a problem that the plasma density does not decrease.

[0017] On the other hand, when the microwave power and the RF bias power are pulsed and synchronized, there is a problem that the etching rate becomes small. In such a case, both the microwave power and the RF bias power as the source power have a cut-off period to some extent, and thus the etching rate will decrease. In addition, depending on the pulse enabling time and duty ratio of the source power, the etching speed becomes very slow.

[0018] In addition, when the RF bias power is applied at the same timing as the pulse oscillation of the microwave power, it is possible to perform etching in a state where the matching with the RF bias power is insufficient. Therefore, due to abnormal discharge and abnormal reflected waves of each power supply, there is a concern about deterioration of in-plane uniformity and reduction of reproducibility of etching.

[0019] In response to this, a method is also to apply the RF bias power after waiting for the elapse of the stabilization time of the plasma after the microwave power is pulsed. As a result, the etching speed distribution becomes uniform and the in-plane uniformity is improved. However, according to such a technique, since there is a zero interval of the RF bias power, side etching progresses, and thus it is impossible to completely avoid poor etching shape.

[0020] Furthermore, it is also possible to binary the pulse oscillation of the microwave power into high / low and apply the RF bias in the low interval of the microwave. However, the problem of this technique is that in the low interval of the microwave, there is almost no deposition component in the plasma and side etching is likely to occur. In addition, it is difficult to achieve the matching of the RF bias power under the plasma that can prevent the plasma from going out until the microwave power is applied.

[0021] In view of the above, a technique is sought to maintain the shape controllability of etching and not reduce the etching rate even when microwave power is pulsed and etching is performed at a low plasma density.

[0022] An object of the present invention is to provide a plasma processing apparatus that can precisely control the etching shape using a microwave power supply capable of oscillating different microwave powers.

[0023] To solve the above problems, one of the plasma processing apparatuses according to the representative present invention is achieved by the following features. The plasma processing apparatus includes: a processing chamber for performing plasma processing on a sample; a first high-frequency power supply for supplying a first high-frequency power for generating plasma; a sample stage for mounting the sample; and a second high-frequency power supply for supplying a second high-frequency power to the sample stage. The plasma processing apparatus further includes: a control device that controls the second high-frequency power supply so as to supply each of the second high-frequency powers of the period A during the first period and the second period when the first high-frequency power is modulated by a first waveform having a first period and a second period adjacent to the first period, and the second high-frequency power is modulated by a second waveform having a period A and a period B, the amplitude of the second period is smaller than the amplitude of the first period and larger than 0, and the amplitude of the period A is larger than the amplitude of the period B.

[0024] Advantages of the Invention

[0025] According to the present invention, a plasma processing apparatus can be provided that can precisely control the etching shape using a microwave power supply capable of oscillating different microwave powers.

[0026] Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic configuration diagram of an ECR plasma etching apparatus which is a plasma processing apparatus according to an embodiment of the present invention.

[0028] Figure 2 It is a graph showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, and (d) RF bias power in the first embodiment.

[0029] Figure 3A It is a graph showing a timing chart of (a) microwave power, (b) plasma density of gas species A, and (c) plasma density of gas species B in the first embodiment.

[0030] Figure 3B (a) of Figure 3AAn enlarged view of the plasma density in (a), (b) is an enlarged cross-sectional view of the pattern shape of the wafer, and (c) is an enlarged cross-sectional view of the pattern shape of the wafer.

[0031] Figure 4A is a diagram showing a timing chart of (a) microwave power, (b) plasma density of gas species A, and (c) plasma density of gas species B in the second embodiment.

[0032] Figure 4B In (a) of Figure 4A An enlarged view of the plasma density in (a), (b) is an enlarged cross-sectional view of the pattern shape of the wafer, and (c) is an enlarged cross-sectional view of the pattern shape of the wafer.

[0033] Figure 5 is a diagram showing an example of a timing chart of (a) pulsed microwave power and (b) pulsed RF bias power in the third embodiment.

[0034] Figure 6 is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, and (d) RF bias power in the fourth embodiment.

[0035] Figure 7 is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, and (d) RF bias power in the fifth embodiment.

[0036] Figure 8A is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, (d) RF bias power, and (e) Vpp in the comparative example.

[0037] Figure 8B is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, (d) RF bias power, and (e) Vpp in the comparative example.

[0038] Figure 9 is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, (d) RF bias power, and (e) Vpp in the sixth embodiment.

[0039] Figure 10 is a diagram showing a timing chart of (a) microwave power, (b) plasma density, (c) plasma impedance, (d) RF bias power, (e) RF bias reflected wave, and (f) Vpp in the seventh embodiment.

[0040] Figure 11A is a schematic structural diagram of an ECR plasma etching apparatus in the eighth embodiment.

[0041] Figure 11B It is a diagram showing the waveform of the microwave power supplied to the ECR plasma etching apparatus for Figure 11A .

[0042] Figure 11C It is a diagram showing the waveform of the RF bias power supplied to the ECR plasma etching apparatus for Figure 11A .

[0043] Figure 12A , Figure 12B , Figure 12C It is an enlarged cross-sectional view showing the etching shape of the wafer processed by the ECR plasma etching apparatus. DETAILED DESCRIPTION

[0044] [First Embodiment]

[0045] Figure 1 It is a schematic structural diagram of a longitudinal section of an ECR-type microwave plasma etching apparatus (hereinafter referred to as plasma processing apparatus 1) according to an embodiment of the present invention. Each part such as the processing chamber, sample stage, and sample in the plasma processing apparatus 1 generally has an axisymmetric shape such as a cylinder, a column, or a circular plate.

[0046] In this specification, "applying power at the time of crossing the switching" means applying power starting from before the switching time and continuing the application of the power until after the switching. For example, it means applying each second high-frequency power during the first period and the second period of the first high-frequency power, etc.

[0047] (Structure of Plasma Processing Apparatus)

[0048] In Figure 1 , a vacuum exhaust device 119 is connected to the lower part of the processing chamber 122 inside the vacuum container 101 of the plasma processing apparatus 1. In addition, a shower plate 102 and a quartz top plate 103 are arranged in the upper part inside the processing chamber 122. The shower plate 102 has a plurality of holes. The gas for plasma etching processing supplied from the gas supply device 120 is introduced into the processing chamber 122 through the holes of the shower plate 102. The quartz top plate 103 is arranged above the shower plate 102, and a gas supply gap is provided therebetween. The quartz top plate 103 allows electromagnetic waves from above to pass through and hermetically seals the upper part of the processing chamber 122.

[0049] Above the quartz top plate 103, a cavity resonator 104 is disposed. The upper part of the cavity resonator 104 is open, and a waveguide 105 is connected thereto. The waveguide 105 is composed of a waveguide transformer having a vertical waveguide extending in the vertical direction and a bent portion that bends the direction of electromagnetic waves by 90 degrees. The waveguide 105 and the like are oscillating waveguides for propagating electromagnetic waves. At the end of the waveguide 105, a microwave power supply 106 for plasma generation is connected via a tuner 107.

[0050] The microwave power supply 106, which is the first high-frequency power supply, is a power supply for plasma generation, and oscillates electromagnetic waves (first high-frequency power) based on the control from the control unit 123. The microwave power supply 106 of the present embodiment can oscillate microwaves of 2.45 GHz. The first high-frequency power is modulated by a first waveform that alternately repeats a high section TH (first period) and a low section TL (second period adjacent to the first period).

[0051] The microwaves oscillated from the microwave power supply 106 propagate in the waveguide 105, and reach the inside of the processing chamber 122 via the cavity resonator 104, the quartz top plate 103, and the shower plate 102. A magnetic field generating coil 109 is disposed on the outer periphery of the processing chamber 122. The magnetic field generating coil 109 is composed of a plurality of coils, and forms a magnetic field in the processing chamber 122. The high-frequency power oscillated from the microwave power supply 106 generates high-density plasma 121 in the processing chamber 122 through the interaction between the magnetic field formed by the magnetic field generating coil 109 and ECR.

[0052] Below the processing chamber 122, a sample stage 110 is disposed opposite to the quartz top plate 103. The sample stage 110 holds the wafer 111 as a sample in a mounted state.

[0053] The sample stage 110 contains aluminum and titanium as materials. On the upper surface of the sample stage 110, there is a dielectric film 112. On the upper surface of the dielectric film 112 of the sample stage 110, a thermal spray film such as aluminum ceramic is disposed.

[0054] In addition, conductive films (electrodes) 113 and 114 for electrostatically adsorbing the wafer 111 are provided inside the dielectric film 112. By applying a DC voltage (not shown), the wafer 111 can be electrostatically adsorbed. Further, a second high-frequency power (hereinafter, referred to as RF bias) is applied to the conductive films 113 and 114 of the sample stage 110 from an RF bias power supply 117, which is a second high-frequency power supply. The second high-frequency power is modulated by a second waveform that repeats an enable section BON (period A) and a cutoff section BOF (period B).

[0055] The RF bias power supply 117 is connected to a matching box (matcher) 115, thereby enabling the matching of the RF bias. The plasma density is changed by the pulsed oscillation of microwaves, and the matching box 115 functions to complete the matching of the RF bias even when the plasma impedance changes at high speed. More specifically, the matching box 115 performs high-speed matching based on solid-state elements, sets a matching interval that invalidates the period during which the plasma load (plasma impedance) changes rapidly and validates the other periods as the matching effective range, fixes the matching that invalidates the chaos of the plasma (load), optimizes the matching based on the prediction of the plasma (load), etc., to achieve matching at the millisecond level.

[0056] The RF bias power supply 117 generates high-frequency power for ion attraction and supplies it to the sample stage 110. The RF bias power supply 117 also generates a pulse-modulated RF bias based on the pulses from the RF bias pulse unit 118.

[0057] In addition, in the RF bias power supply 117 of the present embodiment, the RF bias frequency is not particularly limited, but for example, a frequency of 400 kHz can be used.

[0058] In order to monitor the difference between the maximum value and the minimum value of the voltage in the high-frequency RF bias (V peak-to-peak: hereinafter, simply referred to as Vpp), a voltage monitor (not shown) is provided on the RF bias power supply line.

[0059] A microwave pulse unit 108 is connected to the microwave power supply 106. Through the enable signal from the microwave pulse unit 108, the microwave power supply 106 can pulse-modulate the microwave at a set repetition frequency. The high-frequency power output from the microwave power supply 106 is called microwave power.

[0060] In addition, in order for the microwave power supply 106 to be able to oscillate in the range of 50 W to 2000 W and oscillate accurately with good responsiveness when performing pulse oscillation, a solid-state type microwave power supply is used instead of a magnetron type microwave power supply.

[0061] The control unit 123 is a control device of the plasma etching apparatus, is connected to the microwave power supply 106 and the RF bias power supply 117, and controls the output of the first high-frequency power and the second high-frequency power.

[0062] Although not shown, in addition to this, the control unit 123 is also electrically connected to the gas supply device 120, the vacuum exhaust device 119, the DC power supply 116, etc., and controls them.

[0063] The control unit 123 controls the high power of the microwave power supply 106, the low power of the microwave power supply 106, the high power of the RF bias power supply 117, the low power of the RF bias power supply 117, the timing of enabling / disabling the pulse of the microwave pulse module, and the repetition frequency, duty ratio, delay time, etc. of the enabling / disabling of the RF bias power supply 117, and the parameters of the microwave power supply 106 and the RF bias power supply 117 based on the input setting (also known as the recipe) of an input unit (not shown).

[0064] In addition, besides this, the control unit 123 also controls etching parameters such as the flow rate of the gas used for etching, the processing pressure, the coil current, the sample stage temperature, and the etching time.

[0065] (Operation of the plasma processing apparatus)

[0066] Whenever the etching process is started, the wafer 111 is transported into the processing chamber 122. After adsorbing the wafer 111 onto the sample stage 110, based on the recipe, the etching gas is made to pass between the quartz top plate 103 and the quartz shower plate 102 from the gas supply device 120 via a mass flow controller (not shown) and is introduced into the processing chamber 122 through the gas holes of the quartz shower plate 102. Further, the inside of the vacuum container 101 is set to a given pressure, and plasma 121 is generated in the processing chamber 122 by the oscillation of the microwave power supply 106. In addition, by outputting an RF bias from the RF bias power supply 117, ions are attracted from the plasma 121 to the wafer 111, thereby advancing the etching (plasma processing). The etching gas and the reaction products generated by the etching are exhausted from the exhaust device 119.

[0067] In the present embodiment, the shower plate 102, the sample stage 110, the magnetic field generating coil 109, the vacuum exhaust device 119, the wafer 111, etc. are arranged coaxially with respect to the central axis of the processing chamber 122. Therefore, the etching gas, plasma, saturated ion current, and reaction products respectively have a coaxial distribution. As a result, the uniformity of the etching rate is improved in an axisymmetric distribution.

[0068] Here, the parameters of the microwave pulse and the parameters of the RF bias are set as follows.

[0069] High power P1 of the microwave power supply 106: 600 W (can be changed in the range of 50 - 2000 W),

[0070] Low power P2 of the microwave power supply 106: 150 W (can be changed in the range of 20 - 1600 W),

[0071] High / low frequency F1 of the microwave power: 500 Hz,

[0072] High / low period T1 of the microwave power = 1 / F1 (seconds),

[0073] High / low duty cycle D1 of microwave power: 40%,

[0074] High interval TH of microwave power: 1 millisecond,

[0075] Low interval TL of microwave power: 1 millisecond,

[0076] Enable / cutoff frequency F2 of microwave power: 100 Hz,

[0077] Enable / cutoff period of microwave power: T2 = 1 / F2 (seconds),

[0078] Enable / cutoff duty cycle D2 of microwave power: 80%,

[0079] Enable time T3 of microwave power = T2·D2,

[0080] Enable frequency F3 (=1 / T3) of microwave power: 125 Hz,

[0081] (wherein, the high / low frequency F1 of the microwave power becomes a multiple of the enable frequency F3 of the microwave power. The start time of the high interval TH of the microwave power is set as the reference point PST)

[0082] Enable power of RF bias: 100 W (can be changed in the range of 10 - 500 W),

[0083] Cutoff power of RF bias: 0 W

[0084] High / low period TB (=T1) of RF bias: 2 milliseconds,

[0085] Frequency FB1 (=1 / TB) of RF bias: 500 Hz (can be changed in the range of 10 - 5000 Hz),

[0086] Enable interval BON of RF bias: 1 millisecond,

[0087] Cutoff interval BOF of RF bias: 1 millisecond,

[0088] Duty cycle of RF bias: 30% (can be changed in the range of 1 - 100%),

[0089] Delay time TD of RF bias: 0.6 millisecond,

[0090] Delay RD (=TD / T1) of RF bias: 30%,

[0091] (wherein, the RF bias is not used except during the enable time of the microwave power.)

[0092] Figure 2Shows the sequence when applying an RF bias during the period of crossing the switching from the high range TH of microwave power to the low range TL of microwave power when the above parameter settings are set.

[0093] In Figure 2 it, the graph of the microwave power (a) is shown by 201, the graph of the plasma density (b) is shown by 202, the graph of the plasma impedance (c) is shown by 204, and the graph of the RF bias (d) is shown by 205.

[0094] In this example, in order to obtain high shape controllability in etching, there are restrictions on the pulse time range, the power range of microwaves, and the types of gases used in etching.

[0095] Regarding the types of etching gases, a mixed gas obtained by mixing two or more gases is preferably used. In such a case, a mixed gas of a deposition gas for deposition and a gas that becomes an etchant is further used. In the present embodiment, a mixed gas of chlorine gas (flow rate 100 ml / sec) as the gas for the etchant and CHF3 gas (flow rate 10 ml / sec) as the gas for deposition is used.

[0096] Even if the reaction products obtained by etching with a monomer etchant gas without using the above mixed gas are reattached, there is no problem. For example, in the case of etching silicon with CF4 gas, if the gas for the etchant is CF4 gas and the gas for deposition is regarded as the silicon-based reaction products during silicon etching, the same effect as when using a two-gas mixture can be obtained.

[0097] Next, regarding the power range of microwaves, the low power P2 of microwaves (the amplitude of the second period) is smaller than the high power P1 of microwaves (the amplitude of the first period) and greater than 0. Here, if the difference between the high power P1 of microwaves and the low power P2 of microwaves is small, for example, 20% or less, the change range of the plasma density is small, and there is almost no delay in the plasma density with respect to the change in microwave power, so the effect of the etching shape cannot be obtained.

[0098] On the contrary, when the high power P1 is 1600 watts and the low power P2 is 50 watts or less close to plasma extinction, the difference between the high power P1 of microwaves and the low power P2 of microwaves is large. For example, in terms of plasma density, it exceeds 7.5×10 16 (m -3 ) of plasma, it is difficult to correctly match the RF bias. Or, if the difference between the high power P1 and the low power P2 is large, since the time for transferring from the high range to the low range has to be considered, there will be a problem that the plasma density does not change as Figure 2 the graph 202 shows.

[0099] Generally speaking, when the high power P1 of the microwave ranges from 50 W to 2000 W and the low power P2 of the microwave ranges from 20 W to 1600 W, it is preferable to determine the difference between the high power P1 and the low power P2 such that the low power P2 is 20% or more with respect to the high power P1.

[0100] Describe the high / low frequency F1 of the microwave power and the high / low duty ratio D1 of the microwave power. For the change in the microwave power in the high microwave power range TH and the low microwave power range TL, the plasma density follows with some delay time constant. The time for the plasma density to saturate to a fixed value for the change in the microwave power, or the so-called afterglow time for the plasma density to follow the decrease and go out when the microwave power changes from enabled to cutoff is on the order of about 0.2 to 5 milliseconds.

[0101] If the high / low cycle T1 of the microwave power is further shortened and the high / low frequency F1 of the microwave power is increased, then for the high and low of the microwave power to be repeated at high speed, the plasma density cannot follow, the plasma is unstable, the plasma density does not saturate, and the increase and decrease of the plasma density occur repeatedly. As a result, the plasma density will repeatedly increase and decrease very slightly near the intermediate value.

[0102] From the viewpoint of appropriately applying the RF bias when the plasma density rises, it is difficult to improve the accuracy of the etching shape. In addition, it will cause fluctuations in the pulsed RF bias, and the difficulty of RF bias matching will increase. Based on this, the above situation is also unrealistic.

[0103] On the contrary, if the high / low cycle T1 of the microwave power is extended and the high / low frequency F1 of the microwave power is decreased, then in the transition interval between the high microwave power range TH and the low microwave power range TL, the interval in which the plasma density changes is sufficiently short with respect to the high / low cycle T1 of the microwave power. Therefore, it is not possible to expect an improvement in the accuracy of the etching shape.

[0104] Based on the above, it is preferable to set the high / low frequency F1 of the microwave power to approximately 200 Hz to 5000 Hz and the high / low duty ratio D1 of the microwave power to 10% to 90%. In addition, the control unit 123 preferably controls the matching box 115 after the transfer from the first period to the second period or from the second period to the first period to perform matching of the RF bias power in order to suppress the reflected power of the RF bias power.

[0105] Next, it is okay to set the RF bias frequency FB1 to be the same as the high / low frequency F1 of the microwave power. Among them, the amplitude in the period A (enabled interval BON) of the RF bias power is larger than the amplitude (preferably zero) in the period B (cutoff interval BOF). The application timing of the RF bias is in Figure 2It is important to appropriately apply an RF bias (where the reflected wave of the RF bias is 5% or less of the RF bias power) from the high microwave power range TH to the low microwave power range TL in the shaded area below the curve graph 202 until the plasma density decreases in the range 206.

[0106] As Figure 2 shown in (d) of [], the application of the RF bias is advanced by a time TA earlier than the end of the high microwave power range TH. In other words, the control unit 123 controls the RF bias power supply 117 so as to supply each second high-frequency power during period A in a part of the first period and a part of the second period. When setting the time TA in this case, it is preferable to consider the case where the RF bias is not in a ramp during the RF bias matching operation, and it is further preferable to consider the case where etching progresses in this range.

[0107] In Figure 2 the example of [], the time TA is set to 40% of the high microwave power range TH, but it is actually determined according to the adjustment of the etching shape. For example, in the case of increasing the etching rate and wanting to promote etching under high-density plasma, the time TA can be extended compared to the example of the figure. On the contrary, in the case of wanting to promote etching under low-density plasma and sufficiently suppressing side etching, the RF bias enable time and the RF bias duty ratio can be extended to apply the RF bias in the low microwave power range TL.

[0108] Figure 3A shows the change in plasma density when etching is performed with gases of different types in the above sequence. Figure 3B The change in plasma density is enlarged and shown, and the etching shape at a certain moment is schematically shown.

[0109] Under the above etching conditions, when the microwave power (a) repeats the high microwave power range TH and the low microwave power range TL as shown in the curve graph 301, the plasma density (b) of the etching gas type A (chlorine) is shown in the curve graph 302, and the plasma density (c) of the deposition gas type B (CHF3) is shown in the curve graph 303.

[0110] If the high microwave power range TH is switched to the low microwave power range TL, the plasma density immediately begins to decrease, but as Figure 3B shown in (a) of [], there is a response time, and the plasma density decreases with a delay of some time constants. After that, the curve graphs 302 and 303 asymptotically stabilize at a plasma density corresponding to the low plasma power in the low microwave power range TL.

[0111] When two gases are mixed and used, particularly a deposition gas and an etchant gas, the plasma density of the etchant gas species A (chlorine) changes as shown by the solid line graph 302, and the plasma density of the deposition gas species B (CHF3) changes as shown by the dotted line graph 303. There is a difference in the plasma density time constants of the etchant gas and the deposition gas. Generally, the time constant for the density of the plasma 308 based on the deposition gas is larger (it takes more time to reach the equilibrium state) compared to the plasma 307 based on the etchant gas.

[0112] Therefore, Figure 3B During the period 304 (the period from time 305 to time 306) of the shaded area shown in (a) of, the plasma based on the deposition gas species B (CHF3) is more in proportion compared to the plasma based on the etchant gas. This is the same as the case where only the deposition gas species B is supplied in a larger amount during this short period, resulting in a deposition-rich situation.

[0113] Therefore, if no RF bias is applied during this period 304, unnecessary deposition will form on the sides of the pattern. Not only will it overly become a conical shape, but also ions will not be incident on the bottom of the pattern, preventing vertical etching from progressing. On the other hand, by applying an appropriate amount (e.g., 50 watts) of RF bias during this period 304, it is possible to ensure vertical etching while completely suppressing side etching, or adjusting the sidewall protective film 310 in an appropriate amount to obtain a vertical etching shape. Figure 3B (b) of shows the plasma etching state at time 305, Figure 3B (c) of shows the plasma etching state at time 306.

[0114] Regarding this, it can also be said that even if the ratio of the etchant gas and the deposition gas is changed during this period 304 to make the deposition rich for etching, the same effect is achieved. However, it is not realistic to change the gas in a short period of milliseconds, and since the impact on other etching performances such as the selectivity and uniformity is very large, it is difficult to adjust.

[0115] According to this embodiment, by simply adding the means of applying an RF bias when crossing the switching between the high microwave power range TH and the low microwave power range TL to the existing pulsed parameter method of etching, such as the method of waiting until the plasma is stable and then applying an RF bias, or the method of immediately applying after switching between the high and low intervals of the microwave power, side etching can be suppressed and the shape can be made vertical. Therefore, it will not have a great impact on other etching performances.

[0116] [Second Embodiment]

[0117] Figure 4A In contrast to the example of Figure 3A , the graph shows the plasma density of each gas when an RF bias is applied during the transition from the low microwave power range TL to the high microwave power range TH. Figure 4B The change in plasma density is magnified and the etching shape is schematically represented.

[0118] Here, the plasma processing apparatus 1 of the first embodiment is used. Further, the etching gas, microwave, RF bias power, microwave pulse parameters, etc. are also made common. The difference from the first embodiment is that the RF bias delay time TD is set to 1.6 milliseconds and the RF bias delay RD is set to 80%.

[0119] As Figure 4A shown, when switching from the low microwave power range TL to the high microwave power range TH, the plasma density starts to increase and soon saturates.

[0120] In this embodiment, the plasma density of the etching gas species A (chlorine) changes as shown in the graph 302, and the plasma density of the deposition gas species B (CHF3) changes as shown in the graph 303. During the period 401 (the period from time 402 to time 403) in the shaded area of Figure 4B (a), the plasma phase of the etching gas species A (chlorine) has a higher density than the plasma of the deposition gas species B.

[0121] By enabling the RF bias during this period 401, a large number of chloride ions as etching agents are accelerated by the RF bias and the chloride ions impinge on the bottom of the pattern. As a result, vertical etching progresses and the etch-through performance in the narrow region of the shaped pattern 403 is improved. However, on the other hand, it also has the characteristic that some side etching progresses. Figure 4B (b) shows the plasma etching state at time 402, Figure 4B (c) shows the plasma etching state at time 403.

[0122] If the side etching shape as shown in Figure 12A is obtained in the existing plasma etching, then by applying an RF bias across the transition from the high microwave power range TH to the low microwave power range TL, the etching shape as shown in Figure 12B can be obtained.

[0123] On the contrary, if the tapered side etching shape as shown in Figure 12C is obtained in the existing plasma etching, then it is desirable to apply an RF bias across the transition from the low microwave power range TL to the high microwave power range TH.

[0124] (Third Embodiment)

[0125] Figure 5 This is a diagram showing the parameters and ranges of microwave pulses in a sequence where pulse oscillation can be performed in three stages: a high power P1 of microwaves, a low power P2 of microwaves, and a cut-off power P0 = 0 of microwave power in addition to the above. The change in microwave power (a) is shown in graph 501, and the change in RF bias (b) is shown in graph 502. In this example, the microwave power has a high range TH (first period), a low range TL (second period), and a cut-off range (T2 - T3: third period) with zero amplitude.

[0126] The parameters of the microwave pulse are six: the high power P1 of microwaves, the low power P2 of microwaves, the high / low frequency F1 of microwave power, the high / low duty ratio D1 of microwave power (= TH / T1), the enable / cut-off frequency F2 of microwave power, and the enable / cut-off duty ratio D2 of microwave power (= T3 / T2).

[0127] Thus, the high / low period (T1) of microwave power and the enable / cut-off period (T2) of microwave power are determined, and the enable time (T3) of microwave power and the enable frequency (F3) of microwave power are determined.

[0128] After the microwave power shown in graph 501 is switched from the cut-off state to the enabled state, the outputs of high power (P1) and low power (P2) are repeated multiple times, and then it returns to the cut-off (P0) state. To implement such an output, when the enable frequency of microwave power is F3 and n is a natural number, it is necessary to set F1 > F3 and F1 = n × F3.

[0129] In addition, although etching can be performed when n = 1, in this case, the microwave power is F1 = 1 × F3 = F3, so it becomes a simple repetition of the three stages of cut-off, high, and low of microwave power. However, in this example, even if the RF bias is applied when switching between the high range TH and the low range TL of microwave power as in the first embodiment, sufficient effects cannot be obtained, and it is difficult to control from the viewpoint of RF bias matching. Therefore, it is preferable to set n to 2 or more.

[0130] In Figure 5 Graph 502 shows the pulse parameters of the RF bias corresponding to the microwave power. Basically, it is the same as the first embodiment, and the difference is that outside the enable time T3 of microwave power (i.e., the third period), following the principle of not applying the RF bias, the RF bias is not applied as shown by the dotted line in graph 502 (the amplitude of the RF bias is set to zero).

[0131] By interrupting the application of the RF bias outside the microwave power activation time T3, an effect such as improvement in the in-plane uniformity of the etching (rate) can be obtained. The pulse parameters set in the above-described embodiment for improving the shape controllability have an adverse effect on the in-plane uniformity. In order to balance the improvement in shape controllability and in-plane uniformity, it is set to apply the microwave power in three stages as shown in Figure 5 the manner shown.

[0132] In the ECR type plasma etching apparatus of the present embodiment, depending on the average power of the applied microwave power, unevenness occurs in the etching rate distribution due to the bias of the in-plane distribution of the reaction products generated by plasma etching and the distribution in the plasma processing chamber. In order to correct these, the microwave power activation / deactivation duty ratio is adjusted to optimize the etching rate distribution and in-plane uniformity.

[0133] (Fourth Embodiment)

[0134] Hereinafter, the fourth embodiment will be described. Figure 6 This is a diagram similar to Figure 2 the same in a state where the applied RF bias is also binary-coded into a high power P3 and a low power P4 in addition to binary-coding the oscillating microwave power into a high power P1 and a low power P2. Here, the graph of the microwave power (a) is shown by 601, the graph of the plasma density (b) is shown by 602, the graph of the plasma impedance (c) is shown by 604, and the graph of the RF bias (d) is shown by 605.

[0135] The parameters of the RF bias are six parameters: the high power P3 of the RF bias, the high duty ratio RHD of the RF bias (= BON / TB), the high delay HDL of the RF bias (the time from the reference point PST to the rising edge of the high power P3), the low power P4 of the RF bias, the low duty ratio RLD of the RF bias (= BOF / TB), and the low delay LDL of the RF bias (the time from the reference point PST to the falling edge of the low power P4). In the present embodiment, the period A (activation interval BON) during which the high power P3 of the RF bias is applied is longer than the first period (high interval TH) and longer than the second period (low interval TL).

[0136] As parameters of the microwave power, the high power P1 of the microwave is set to 600 W, the low power P2 of the microwave is set to 150 W, the enabled power of the RF bias is set to 100 W, the high / low cycle T1 of the microwave power is set to 2 ms, the high / low frequency F1 of the microwave power is set to 500 Hz, the high interval TH of the microwave power is set to 1 ms, the high / low frequency of the RF bias is set to 500 Hz, the high duty ratio RHD of the RF bias is set to 70%, the low duty ratio RLD of the RF bias is set to 30%, the high delay HDL of the RF bias is set to 50%, the low delay LDL of the RF bias is set to 20%. At this time, the change in the applied RF bias becomes as shown in the graph 604.

[0137] The parameters of the RF bias are not particularly limited. Among them, when the RF bias also repeats the high interval and the low interval in the same way as the pulse parameters of the microwave power, that is, when there is no RF bias cut-off within one cycle of the RF bias, the sum of the "high duty ratio RHD of the RF bias" and the "low duty ratio RLD of the RF bias" must be 100%, and each duty ratio of the RF bias and each delay of the RF bias must be an appropriate percentage.

[0138] In Figure 6 In the example shown, since the high delay HDL of the RF bias is 50% and the high duty ratio RHD of the RF bias is 70%, their sum is 120%. Further, the low delay LDL of the RF bias is 20%. If the 30% of the low duty ratio RLD of the RF bias is added, it becomes the original RF high delay.

[0139] Here, when switching from the high interval TH of the microwave power to the low interval TL of the microwave power, the switching from the low interval TL of the microwave power to the high interval TH of the microwave power is all performed within the enabled interval of the high power of the RF bias. As one of the effects, the balance between the side and conical etching shapes can be achieved using the above-described embodiment. Another effect is that the variation of Vpp can be suppressed as much as possible as Figure 9 shown, and the details will be described later.

[0140] (Embodiment 5)

[0141] Describe Embodiment 5. Figure 7 It is the same figure as Figure 6 In Figure 7In this case, six parameters of the same RF bias as in the fourth embodiment are used. At the timing of switching from the high microwave power range TH to the low microwave power range TL, a high power P3 of the RF bias is applied. At the same time, at the timing of switching from the low microwave power range TL to the high microwave power range TH, a low power P4 of the RF bias is applied. The change in the RF bias supplied at this time is shown in the graph 704. Here, for simplicity, the magnitudes of the high power P3 of the RF bias and the low power P4 of the RF bias are set to be the same. That is, the RF bias repeats its change in a pulsed manner between zero and P3.

[0142] Here, as parameters of the microwave power, the high power P1 of the microwave is set to 600 watts, the low power P2 of the microwave is set to 150 watts, the enabling power P3 of the RF bias is set to 100 watts, the high / low cycle T1 of the microwave power is set to 2 milliseconds, the high / low frequency F1 of the microwave power is set to 500 hertz, the high range TH of the microwave power is set to 1 millisecond, the high duty ratio RHD of the RF bias is set to 30%, the low duty ratio RLD of the RF bias is set to 35%, the high delay HDL of the RF bias is set to 35%, and the low delay LDL of the RF bias is set to 90%.

[0143] In this case, there is no such restriction that the sum of the "high duty ratio of the RF bias" and the "low duty ratio of the RF bias" is 100%.

[0144] In this embodiment, a method of applying the RF bias only at the timings of increasing and decreasing the plasma density is selected. This embodiment is preferably used in extreme etching control cases, for example, in cases where although it is desired to completely form a deposition film on the sidewalls of the pattern, it is desired to reliably advance the etching of the bottom of the pattern; or in cases where, compared to the uniformity of the in-plane distribution of the etching surface, it is desired to advance the cyclic etching of repeating deposition and etching in a short time.

[0145] (Comparative example)

[0146] A comparative example is described. Figure 8A 、 8B is the same figure as Figure 7 but Vpp is added to (e). Similar to the above-described embodiment, it is a method of supplying the microwave power by alternately repeating the high range TH and the low range TL of the microwave power in a pulsed manner. However, in Figure 8A shown as the first comparative example, as shown in the graph 801, the RF bias is a continuous wave (fixed). The change in Vpp of the voltage on the sample stage at this time is shown in the graph 802.

[0147] On the other hand, in Figure 8BIn this case, as shown in the graph 803, high power of the RF bias is applied simultaneously with the start of the high microwave power range TH, and low power of the RF bias is applied simultaneously with the start of the low microwave power range TL. The change in Vpp of the voltage on the sample stage at this time is shown in the graph 804.

[0148] If a continuous wave RF bias is applied as shown in the graph 801, Vpp increases or decreases corresponding to the increase or decrease of the plasma impedance. In the continuous wave RF bias, since the RF bias matching is also performed at an arbitrary timing (successively), the reflected wave is also generated corresponding to the increase or decrease of the plasma impedance, and thus the variation of Vpp may be further greater than that in the graph 802.

[0149] Next, as Figure 8B shown, in the method of applying high power of the RF bias simultaneously with the start of the high microwave power range TH and applying low power of the RF bias simultaneously with the start of the low microwave power range TL, the RF bias changes as shown in the graph 803 with respect to the increase or decrease of the plasma density and the plasma impedance. Therefore, Vpp in the high range of the RF bias in the second half of the high microwave power range TH and Vpp in the low range of the RF bias in the second half of the low microwave power range TL are substantially equal.

[0150] However, changing the magnitude of the RF bias at the moment of switching to the low microwave power range TL has a considerable impact on the reflected wave of the RF bias and the variation of Vpp. One of the impacts is that due to the competition between the change of the RF bias and the matching operation, sometimes the matching point cannot be found, or it becomes an operation in the opposite direction to the matching. As a result, sometimes it takes more time than the normal matching completion time. As a result, it may not be possible to apply the RF bias and Vpp to the sample stage appropriately. Therefore, it is preferable to apply the RF bias across the high / low switching of the microwave power.

[0151] (Embodiment 6)

[0152] Describe Embodiment 6. Figure 9 is the same figure as Figure 8B and is a figure showing a sequence representing the relationship between microwave power, RF bias, and Vpp. The graph of the microwave power (a) is shown by 901, the graph of the plasma density (b) is shown by 902, the graph of the plasma impedance (c) is shown by 903, the graph of the RF bias (d) is shown by 904, and the graph of Vpp (e) is shown by 905.

[0153] As shown in the graph 904, the RF bias changes from low power to high power before switching from the low microwave power range TL to the high microwave power range TH, and further changes from high power to low power after switching from the high microwave power range TH to the low microwave power range TL.

[0154] As the RF bias increases, Vpp becomes larger, but the plasma density has stabilized and there is almost no reflected wave. After that, if the microwave power is switched from the low range TL to the high range TH, the plasma density increases. On the contrary, the plasma impedance decreases. As a result, Vpp decreases, the plasma impedance stabilizes, and Vpp also stabilizes.

[0155] Next, if the microwave power is switched from the high range TH to the low range TL, Vpp also increases along with the increase in impedance. However, since the RF bias is switched to low power during the rise, Vpp turns to decrease. Although there are some variations due to the matching form of the RF bias, the variation of Vpp is as shown in the graph 905. Specifically, each time the microwave power is switched between the high range TH and the low range TL, Vpp shows some behaviors of increase and decrease, but the direction of the change in Vpp is the same, and the variation amplitude of Vpp is Figure 8A 、 Figure 8B is very small compared to the way of

[0156] If etching is carried out in a state where the variation amplitude of Vpp is large, the following problems will occur. One of the problems is related to the reproducibility and stability of the etching process. Specifically, due to the difference in the application timing of the microwave power and the RF bias, Vpp changes greatly, resulting in poor etching performance, which further becomes a cause of equipment differences.

[0157] Another problem is related to the flatness and roughness of the etching shape. If etching is carried out while the Vpp of the RF bias changes greatly, the ion incidence on the pattern sidewall and the pattern bottom surface may deviate along the time axis, and pattern cracking may occur. In some cases, poor etching shapes such as scallop patterns (folding) may occur, which may deteriorate the electrical performance of the components formed by the wafers on which the etching process has been carried out. According to the present embodiment, such adverse conditions can be suppressed.

[0158] (Embodiment 7)

[0159] Describe Embodiment 7. Figure 10 is the same figure as Figure 2 , (e) shows the change of the RF bias reflected wave, and (f) shows the change of Vpp. Refer to Figure 10 , and describe the matching method of the RF bias carried out in the matching box 115.

[0160] In the present embodiment, the RF bias has been applied before switching from the high microwave power range TH to the low microwave power range TL.

[0161] However, in the interval just after the start of the RF bias, the matching effective period is not entered under the setting of the RF bias. As a result, the matching operation of the RF bias is not performed. Although the plasma density approaches the saturation (stable) region corresponding to the application of high microwave power, as shown in the graph 1004, there will be some reflected waves of the RF bias. The graph 1005 shows the change in the effective Vpp of the 400 KHz RF bias applied to the sample stage. Since the plasma density is the highest in the interval just after the start of the RF bias application, as shown in the graph 1001, the plasma impedance is the lowest and the Vpp of the RF bias is small. Considering the reflected wave of the RF bias and the ramp of the RF bias power, in the region where Vpp gradually increases and just stabilizes, the high microwave power interval TH ends.

[0162] After that, although the high microwave power interval TH is switched to the low microwave power interval TL, the application of the RF bias is maintained. If immediately after this switch, the plasma density decreases and the plasma impedance increases as shown in the graph 1001, then Vpp increases accordingly. For the impedance during this increase, it is set to achieve the matching of the RF bias.

[0163] Since the plasma impedance suddenly increases as shown in the graph 1001, it is difficult to make the reflected wave completely zero. Nevertheless, in Figure 10 the central interval (referred to as the matching point) of the shaded matching region in, the reflected wave of the RF bias becomes the smallest and Vpp becomes the largest.

[0164] After that, as shown in the graph 1001, the rising speed of the plasma impedance slows down. Even if the matching of the RF bias is lost, the reflected wave becomes small enough to be negligible and Vpp does not decrease.

[0165] The above operations are periodically repeated according to the high / low microwave power cycle T1. However, by maintaining (without changing) the obtained matching point, substantially the same matching result can also be obtained.

[0166] More preferably, it is also possible to adopt a method of calculating the average plasma impedance just after the switch from the high microwave power interval TH to the low microwave power interval TL and achieving matching for this.

[0167] Similar to the above-described embodiment, preferably, basically, in the interval prior to the high microwave power interval TH and the low microwave power interval TL, it is set to the state where the RF bias has already been applied. The average value of the plasma impedance just after the switch of the high microwave power interval TH and the low microwave power interval TL is set as the matching point of the RF bias, and the timing of the change in the plasma density is searched to apply the RF bias.

[0168] (Embodiment 8)

[0169] Describe the eighth embodiment. Figure 11A It is a schematic cross-sectional view of a plasma processing apparatus having two sets of microwave power supply devices and two sets of RF bias power supply devices. Figure 11B It is a graph showing the change in microwave power used in this embodiment, Figure 11C It is a graph showing the change in RF bias used in this embodiment.

[0170] The first microwave power supply device includes an inner peripheral microwave power supply 1101, an inner peripheral waveguide 1113, and an inner peripheral cavity resonator 1115. The second microwave power supply device includes an outer peripheral microwave power supply 1102, an outer peripheral waveguide 1114, and an outer peripheral cavity resonator 1116. The inner peripheral microwave pulse component 1103 controls the output of the inner peripheral microwave power supply 1101, and the outer peripheral microwave pulse component 1104 controls the output of the outer peripheral microwave power supply 1102.

[0171] The two RF bias power supply devices are an inner peripheral RF bias power supply 1105 and an outer peripheral RF bias power supply 1106, which are respectively connected to the inner peripheral conductive film 1117 of the electrode and the outer peripheral conductive film 1118 of the electrode via matching boxes.

[0172] The inner peripheral RF bias pulse component 1107 controls the output of the inner peripheral RF bias power supply 1105, and the outer peripheral RF bias pulse component 1108 controls the output of the outer peripheral RF bias power supply 1106.

[0173] The two microwave power supplies can oscillate the microwave power in a pulsed manner (pulse modulation by repeating enabling / disabling), or oscillate in a continuous wave (without pulse modulation). The two RF bias power supplies can also apply the RF bias in a pulsed manner (pulse modulation by repeating enabling / disabling), or apply it in a continuous wave (without pulse modulation).

[0174] As Figure 11A shown in the curve graph 1109, the microwave power is oscillated by repeating enabling / disabling from one microwave power supply, and a continuous wave is oscillated from the other microwave power supply. Thus, through the sum of the microwave powers applied in the processing chamber, as Figure 11B shown in the curve graph 1111, an oscillation mode with three stages of high / low / cutoff of the microwave power can be achieved, and the microwave power as shown in Figure 5 (a) can be achieved.

[0175] Furthermore, for the two RF bias power supplies, if, as Figure 11A shown in the curve graph 1110, similar to the microwave power, the application of one RF bias is binary-coded into the enabling power / cutoff power of the RF bias and applied, and the other RF bias is applied as a continuous wave, then the total amount of RF bias applied to the sample stage is as Figure 11CAs shown in the curve graph 1112, it is possible to implement an application method with three stages of high power / low power / power cut-off for RF bias.

[0176] For the matching of RF bias, it is important to adjust the matching on the pulse side of enabling / disabling the RF bias. It is preferable to set only the interval just after switching from the power enabling of the microwave power supply to the power cut-off as the matching effective interval.

[0177] Furthermore, compared with the above, in the case where each microwave power supply can be in three stages of high / low / cut-off of microwave power, it is possible to combine them to oscillate, for example, five-stage microwave power. Similarly, the RF bias power supply can also apply a five-stage RF bias with a combination of high / low / cut-off of multiple RF biases.

[0178] Although there is a concern about the complication of the application timing of the enabling power of the RF bias, basically in the microwave power cut-off interval, as long as the principle of not applying all the RF biases is followed, the above-described embodiment can be further refined with high precision, and a further improvement in the control of the etching shape can be achieved.

[0179] In this embodiment, all the RF bias power supplies are set to the same oscillation frequency (400 kHz), but even if the frequencies of two RF bias power supplies are different (for example, 400 kHz and 2 MHz), the same effect is obtained. It is possible to expect an improvement in in-plane uniformity by applying biases with different frequencies of multiple RF biases.

[0180] The oscillation frequencies of each microwave power supply can also be different (for example, 2.45 GHz and 915 MHz). In such a case, it is possible to suppress the separation and interference of microwaves from the inner peripheral microwave power supply and microwaves from the outer peripheral microwave power supply, and similarly to the RF bias, an improvement in the control of in-plane uniformity can be expected.

[0181] The above-described embodiment has been described using an ECR type plasma etching apparatus, but it can also be similarly applied to plasma etching apparatuses corresponding to plasma generation methods such as capacitively coupled plasma and inductively coupled plasma. One of the above-described embodiments can also be combined with other embodiments.

[0182] Explanation of reference numerals

[0183] 1... Plasma processing apparatus, 101... Vacuum chamber, 102... Shower plate, 103... Quartz top plate, 104... Cavity resonator section, 105... Waveguide, 106... Microwave power source, 107... Tuner, 108... Microwave pulse module, 109... Magnetic field generating coil, 110... Sample stage, 111... Wafer, 112... Dielectric film, 113, 114... Conductive film, 115... Matching box, 117... RF bias power source, 118... RF bias pulse module, 119... Vacuum evacuation device, 120... Gas supply device, 121... Plasma, 122... Processing chamber, 123... Control section, 1101... Inner peripheral microwave power source, 1102... Outer peripheral microwave power source, 1103... Inner peripheral microwave pulse module, 1105... Inner peripheral RF bias power source, 1106... Outer peripheral RF bias power source, 1107... Inner peripheral RF bias pulse module, 1108... Outer peripheral RF bias pulse module

Claims

1. A plasma processing apparatus, characterized in that, Comprising: A processing chamber for performing plasma processing on a sample; a first high-frequency power supply for supplying a first high-frequency power for generating plasma; a sample stage for placing the sample; and a second high-frequency power supply for supplying a second high-frequency power to the sample stage, The plasma processing apparatus further comprises: a control device that controls the second high-frequency power supply to supply each of the second high-frequency powers of the period A during the first period and the second period when modulating the first high-frequency power by a first waveform having a first period, a second period adjacent to the first period, and a third period with an amplitude of 0, and modulating the second high-frequency power by a second waveform having a period A and a period B, The amplitude of the second period is smaller than the amplitude of the first period and larger than 0, The amplitude of the period A is larger than the amplitude of the period B.

2. A plasma processing apparatus, characterized in that, Comprising: A processing chamber for performing plasma processing on a sample; a first high-frequency power supply for supplying a first high-frequency power for generating plasma; a sample stage for placing the sample; and a second high-frequency power supply for supplying a second high-frequency power to the sample stage, The plasma processing apparatus further comprises: a control device that controls the second high-frequency power supply to supply each of the second high-frequency powers of the period A during the first period and the second period when modulating the first high-frequency power by a first waveform having a first period and a second period adjacent to the first period, and modulating the second high-frequency power by a second waveform having a period A and a period B, The first high-frequency power supply comprises a high-frequency power supply for supplying a high-frequency power without pulse modulation and a high-frequency power supply for supplying a high-frequency power with pulse modulation, The amplitude of the second period is smaller than the amplitude of the first period and larger than 0, The amplitude of the period A is larger than the amplitude of the period B.

3. A plasma processing apparatus, characterized in that, Comprising: A processing chamber for performing plasma processing on a sample; a first high-frequency power supply for supplying a first high-frequency power for generating plasma; a sample stage for placing the sample; and a second high-frequency power supply for supplying a second high-frequency power to the sample stage, The plasma processing apparatus further comprises: a control device that controls the second high-frequency power supply to supply each of the second high-frequency powers of the period A during the first period and the second period when modulating the first high-frequency power by a first waveform having a first period and a second period adjacent to the first period, and modulating the second high-frequency power by a second waveform having a period A and a period B, The second high-frequency power supply comprises a high-frequency power supply for supplying a high-frequency power without pulse modulation and a high-frequency power supply for supplying a high-frequency power with pulse modulation, The amplitude of the second period is smaller than the amplitude of the first period and larger than 0, The amplitude of the period A is larger than the amplitude of the period B.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein, The control device controls the second high-frequency power supply to supply each of the second high-frequency powers of the period A during a part of the first period and a part of the second period.

5. The plasma processing apparatus according to claim 4, wherein the amplitude of period B is 0.

6. The plasma processing apparatus according to any one of claims 1 to 3, wherein period A is longer than the first period.

7. The plasma processing apparatus according to claim 6, wherein the amplitude of period B is 0.

8. The plasma processing apparatus according to claim 1, wherein the control device controls the second high-frequency power supply so as not to supply the second high-frequency power during the third period.

9. The plasma processing apparatus according to any one of claims 1 to 3, wherein the plasma processing apparatus further includes: a matcher that suppresses the reflected power of the second high-frequency power, and the control device controls the matcher so as to match the second high-frequency power after the transition from the first period to the second period or after the transition from the second period to the first period.

10. The plasma processing apparatus according to any one of claims 1 to 3, wherein period A is longer than the second period.

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