JP2007115867A - Plasma processor and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processor provided with a function to use an optimum monitor signal for phase control, and also to provide a method for controlling the plasma processor. <P>SOLUTION: A first RF voltage is supplied to a first electrode provided within a vacuum vessel or at the external side of vacuum vessel from a first RF power source provided at the external side of the vacuum vessel of the plasma processor. A second RF voltage is then supplied, from a second RF power source provided at the external side of the vacuum vessel, to a second electrode provided within the vacuum vessel with the upper surface thereof allowing the setting of a sample. Accordingly, a phase difference between the second RF voltage and a third RF voltage supplied from a third RF power source is controlled with the signal used for measurement of the RF voltage of the first electrode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to semiconductor manufacturing technology. In particular, the present invention relates to a plasma processing apparatus suitable for plasma processing of a semiconductor wafer using plasma and a method for controlling the plasma processing apparatus.

  As semiconductor devices have been highly integrated in recent years, circuit patterns have been increasingly miniaturized, and the required processing dimension accuracy has become increasingly severe. Also, the wafer diameter has been increased to 300 mm for the purpose of reducing the manufacturing cost of semiconductor devices, but for the purpose of increasing the yield, plasma is made uniform in a wide range from the center of the wafer to the vicinity of the outer periphery, and high quality is achieved. Therefore, it is required that uniform processing can be performed. At the same time, it is required to reduce contamination of the wafer by a metal material or the like caused by reduction of foreign matters or scattering due to sputtering.

  In order to achieve such an object, conventionally, in a parallel plate type plasma generator composed of an upper metal plate electrode and a lower wafer (operating as an electrode), each of the upper electrode and the lower electrode (wafer) is provided. A technique is known in which a high frequency bias having the same frequency is applied, a high frequency phase between the biases is controlled, and plasma is made uniform (see, for example, Patent Document 1).

In addition, by controlling the phase of the high frequency between the upper and lower biases, there is a technique for reducing charging damage by improving the uniformity of plasma and reducing the amount of foreign matter generated, while either upper or lower electrode always operates as ground. It is known (see, for example, Patent Documents 2 and 3).
Japanese Patent Laid-Open No. 2001-127045 JP 2002-184766 A JP 2004-111432 A

  However, the conventional technology has a high-frequency phase difference detection means and adjustment means between the upper and lower biases in order to improve the uniformity of the plasma, reduce the amount of foreign matter generated, and reduce charging damage. Although it is supposed to be controlled, there is a problem that even if the phase difference is controlled to 180 degrees by the conventional method, it cannot be guaranteed that the phase difference of the voltage actually appearing on the upper and lower electrodes is 180 degrees. is there. In these methods, phase information is obtained at a matching unit of an application circuit that applies a high frequency bias to the upper and lower electrodes. However, the high frequency applied to the upper and lower electrodes has various phase fluctuation factors after the output unit of the matching unit. For example, with respect to a bias high-frequency application circuit to the upper electrode, another high-frequency circuit for generating plasma that passes through a high-frequency filter or the like exists as a load of the bias high-frequency circuit, and the high-frequency transmission path to the upper electrode is the upper electrode There are features such as being unique. On the other hand, with regard to the bias high frequency application circuit to the lower electrode, a structure for controlling the temperature of the mounted wafer exists in the transmission path of the high frequency bias, and an electrostatic chuck circuit for the wafer exists as a load in the transmission path of the high frequency bias. In addition, a mechanical part such as a wafer transfer mechanism and a cover for protecting them are present as the ground of the high-frequency bias transmission path. That is, although phase information is obtained by each matching unit of the upper and lower electrodes, there is no guarantee that the phase difference of the voltage generated at the electrodes is controlled because the high-frequency transmission path to the subsequent electrodes is different.

  Since the phase shift due to the power path is due to stray capacitance and coil components existing in the power path, the phase shift increases as the frequency increases. Although depending on the configuration of the apparatus, the effect of phase shift is generally significant at a frequency of 1 MHz or higher.

  From the above, it can be said that the phase difference between the voltages generated at the upper and lower electrodes should be determined by the entire high-frequency circuit passing through each electrode and the high-frequency frequency. In this method, the phase difference cannot be accurately detected during wafer processing, so that the phase difference cannot be accurately controlled.

  It is an object of the present invention to provide a plasma processing apparatus and a control method for the plasma processing apparatus that can accurately control the phase difference between the upper and lower electrodes.

  The present invention includes a vacuum vessel in which plasma is generated in a vessel, a first high-frequency power source, a second high-frequency power source, a third high-frequency power source, and a first high-frequency power source provided outside the vacuum vessel. A first electrode provided in or outside the vacuum container to which a first high-frequency voltage and a third high-frequency voltage from the third high-frequency power source are supplied, and a sample is placed on the top surface of the first electrode. A second electrode provided in the vacuum vessel to which a second high-frequency voltage from a second high-frequency power source is supplied, and a signal obtained by measuring the high-frequency voltage of the first electrode or the second electrode, And a phase control device for controlling a phase difference between the second high-frequency voltage and the third high-frequency voltage.

  According to the present invention, in the phase control of each voltage waveform of the third high-frequency power and the second high-frequency power that applies a bias to the processing substrate, the phase difference between the upper and lower electrodes can be accurately detected without detecting the phase. Can be controlled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing the overall structure of the plasma processing apparatus according to the first embodiment of the present invention.
The plasma processing apparatus has a vacuum vessel 1 made of a conductor such as aluminum, and an antenna 2 and a shower plate 3 are attached to the inside thereof by respective shower plate support flanges 5 and 6. The vacuum vessel 1 is grounded. Between the antenna 2 and the shower plate 3, a gas is supplied from the atmosphere side via the process gas introduction pipe 7, and is jetted into the vacuum vessel 1 through a number of micro holes formed in the shower plate 3. It has become. Here, the antenna 2 is naturally formed of a conductor, but the shower plate 3 may be formed of a conductor / dielectric or semiconductor. When the shower plate 3 is formed of a conductor or a semiconductor, the shower plate 3 operates as an antenna that directly transmits power to plasma. The process gas is exhausted by the vacuum exhaust device 11 through the exhaust duct 10 and maintained at a pressure suitable for the process.

  By supplying a predetermined power of a predetermined frequency from the first high-frequency power source 4 to the antenna 2 through the matching unit 28, a plasma 9 having characteristics suitable for the process is generated. The magnet (electromagnet) 8 may be used to control the plasma characteristics, but may be omitted.

  A wafer (processing substrate) 12 is carried into the vacuum vessel 1 from the atmosphere side through a carry-in port (not shown), and is placed on the processing electrode 14 by an appropriate delivery device (not shown). An upper surface of the processing electrode 14 has an electrostatic adsorption film (not shown) having appropriate characteristics, and is electrostatically adsorbed by a voltage applied from the DC power source 23 through the choke coil 22 from the outside. Further, the processing electrode 14 has a coolant groove 15 inside, and is supplied with a coolant from the outside (not shown), and the wafer 12 is adjusted to a temperature suitable for the process. A focus ring 13 is provided on the outer periphery of the wafer 12, and a susceptor 16 is provided for protecting the processing electrode 14 from the plasma 9. The processing electrode 14 is attached to the vacuum vessel 1 via an insulating base 17 and an electrode base flange 18. The processing electrode 14 can be moved up and down by an appropriate vertical mechanism (not shown), and the interval between the wafer 12 and the shower plate 3 may be made variable. The present invention can be applied regardless of the presence or absence of the vertical mechanism.

  High frequency power is applied to the processing electrode 14 from the second high frequency power source 21 through the conductor protected by the insulating tube 19 and the matching unit 20, and a high frequency bias is applied to the wafer 12. As described above, the first high-frequency power source 4 and the matching unit 28 do not need to follow the configuration shown in this figure. For example, the output is applied to the processing electrode 14 in parallel with the second high-frequency power source 21 and the matching unit 20. May be. Further, the first high-frequency power source 4 is not provided, and the second high-frequency power source 21 may be used for both generating the plasma 9 and applying a high-frequency bias to the wafer 12.

  A signal output from the oscillator 30 passes through the phase controller 26, is output from one of the outputs, and is input to the second high-frequency power source 21. The other output of the phase controller 26 is a signal having a controlled phase difference with respect to the signal going to the second high-frequency power source 21, and is input to the third high-frequency power source 25. The output of the third high frequency power supply 25 is mixed with the output of the first high frequency power supply 4 by the mixer 27 through the matching unit 24 and applied to the upper electrode 2 (or the shower plate 3).

  The mixer 27 not only mixes the outputs of the first high-frequency power supply 4 and the third high-frequency power supply 25, but also the output of the first high-frequency power supply 4 enters the third high-frequency power supply 25 and its matching unit 24. It has a filter function to prevent this. Furthermore, the mixer 27 has a filter function that prevents the output of the third high-frequency power supply 25 from entering the first high-frequency power supply 4 and its matching device 28. As described above, a high-frequency bias whose phase is controlled can be applied to the upper electrode 2 (or shower plate 3) and the lower processing electrode 14 (or wafer 12) facing each other at the same frequency.

  Since the frequency of the first high-frequency power source 4 generates plasma, a frequency of about 13.56 MHz or about 2.4 GHz can be used. On the other hand, the main purpose of the frequencies of the second high-frequency power source 21 and the third high-frequency power source 25 is to apply a bias rather than to generate plasma. Usually, a frequency of 13.56 MHz or lower is used. Available.

Here, the relationship between the phase difference between the upper and lower electrodes used in the present invention and the high-frequency voltage will be described with reference to FIG.
FIG. 2 shows the relationship between the RF potential on the wafer surface, the plasma space potential (Vs), and the sheath voltage. The Peak-to-Peak voltage Vpp and the self-bias voltage Vdc of the RF potential waveform are defined in the figure. The self-bias voltage Vdc is a potential at which the sum of the electron current and ion current flowing from the plasma into the electrode becomes exactly zero during one high frequency period, and is a time average value of the surface voltage of the electrode. On the other hand, the plasma space potential (Vs) takes a constant value (defined as Vs0 in FIG. 2) while the RF voltage is sufficiently low, but when the RF potential becomes equal to or higher than the plasma space potential (Vs0), the RF potential And is nearly equal to the RF potential at the maximum value of the RF potential (defined as V0p in FIG. 2). The reason why the plasma space potential is increased by being dragged to the RF potential is that a large amount of electrons are extracted from the plasma due to the increase of the RF potential, so that the plasma becomes ion rich. Here, the ratio of Vdc to Vpp (Vdc / Vpp) is determined by the high frequency and the impedance of the earth as viewed from the wafer. The higher the frequency of the high frequency, the higher the impedance of the ground portion. / Vpp approaches 0. That is, Vdc / Vpp is a value unique to the apparatus, and further to the upper and lower electrodes, that is, the antenna 2 and the electrode 14.
The solid line indicates the case where the potentials of the upper and lower electrodes, that is, the antenna 2 and the electrode 14 are in phase (the phase difference is 0 °), and the dotted line indicates that the potentials of the upper and lower electrodes, that is, the antenna 2 and the electrode 14 are reversed. The case of phase (phase difference is 180 °) is shown. It is shown that when the phase is reversed (phase difference is 180 °), the plasma space potential (Vs) is minimized, that is, the self-bias voltage Vdc is maximized in the negative direction.

  The case where the phase difference is detected by the conventional method and the effect of detecting the high frequency voltage of the present invention will be described with reference to FIG. FIG. 3A shows a state where the phase difference between the antenna 2 high-frequency voltage and the electrode 14 high-frequency voltage is 180 °. As described above, the self-bias voltage Vdc is maximized in the negative direction. On the other hand, FIG. 3B shows the output power states of the matching unit 24 and the matching unit 20 when the antenna 2 high-frequency voltage and the electrode 14 high-frequency voltage are in the state shown in FIG. As shown in FIG. 3B, the high-frequency voltage of the matching unit 24 has a phase delay Ta caused by the filter built in the mixer 27 and the high-frequency transmission path from the matching unit 24 to the antenna 2. I understand. Similarly, a phase delay Tb is also generated in the high-frequency transmission path between the matching unit 20 and the electrode 14. Due to the deviation based on these delays Ta and Tb, even if the phase difference is obtained based on the phase detected by each matching unit, the phase difference is 180 ° − (Ta + Tb). The phase difference cannot be detected correctly.

Therefore, the present inventors examined a configuration that does not require the phase information to be detected directly. Specifically, a detector (an oscilloscope, a high voltage probe, etc.) is directly connected to the antenna 2 and the processing electrode 14, information (Vpp, V0p, Vdc) obtained from these detectors, the antenna 2 and the processing electrode 14. The relationship of the phase difference of the high frequency voltage was investigated and examined. The result is shown in FIG.
FIG. 5 shows the correlation between the phase difference and Vdc / Vpp measured with the antenna 2 and the processing electrode 14. According to this, it can be seen that Vdc / Vpp is correlated in both the antenna 2 and the processing electrode 14, and the phase difference is almost 180 ° where Vdc / Vpp shows the minimum value.
That is, it can be said that phase control can be performed if the Vdc and Vpp of the antenna 2 or the processing electrode 14 can be measured without directly measuring phase information that is very likely to be shifted at the measurement position.

  Based on the above viewpoint, this embodiment includes a high-voltage probe 31 that directly measures the potential of the antenna 2 that is the upper electrode (see FIG. 1). The high voltage probe 31 can directly measure Vpp, Vdc, and V0p of the antenna 2. The high voltage probe 31 is connected to the phase controller 26, and the detected value is used for phase control. The high voltage probe 31 may be connected to the electrode 2 instead of the antenna 2.

Next, the phase controller 26 will be described with reference to FIG. The block diagram of FIG. 4 is a circuit configuration in the phase controller 26.
For detection of Vpp and V0p, the high-frequency voltage of the antenna 2 detected by the high-voltage probe 31 is divided by the high-voltage dividing unit. Although the optimum value of the voltage division ratio varies depending on the absolute value of Vpp, it is usually about 1000: 1. It is desirable to remove harmonic components with a small signal bandpass filter after voltage division. Further, a small signal after passing through the filter is detected by a Vpp detection circuit such as a full-wave rectification circuit in the case of Vpp, and is detected by a V0p detection circuit such as a half-wave rectification circuit in the case of V0p and converted into a DC signal. . The converted signal is taken into the control unit by A / D conversion.
Further, Vdc uses a voltage obtained by cutting a high-frequency component with a low-pass filter or the like and divided by a resistor in the Vdc detection circuit as a detection value. Since the absolute value of Vdc may theoretically be considered to be half the absolute value of Vpp, the voltage division ratio is set to about 500: 1. The divided signal voltage is A / D converted and input to the control unit. For example, a signal level of about 0 to 10 V full scale can be used.
The control unit calculates a command value for the high frequency power supplies 21 and 25 based on a predetermined rule (described later), and outputs it as a digital signal. The output command value is converted into an analog signal by the D / A converter, and is output to the high frequency power supplies 21 and 25 as a sine wave external transmission signal through a phase shifter such as a splitter / shifter circuit. Based on the external oscillation signal of the phase shifter, power is supplied from the high frequency power source to the upper and lower electrodes through each matching unit. A signal is also output from the phase shifter to the transmitter 30.
The output from the control unit is D / A converted and input to the phase shifter. However, a divider circuit constituted by an operational amplifier or the like may be used.

  Next, a wafer processing sequence using the plasma processing apparatus of FIG. 1 will be described. First, the vacuum container 1 is evacuated by the vacuum evacuation device 11 so that the degree of vacuum is below a predetermined level. At this time, it is confirmed that the gas leakage amount from the process gas introduction pipe 7 and the atmosphere is sufficiently low in the vacuum container 1. At the same time, it is confirmed that the amount of outgas from the components in the vacuum vessel 1 is sufficiently low. In this state, the processing substrate (wafer) 12 is mounted on the processing electrode 14. Next, a process gas is introduced into the vacuum vessel 1 from the process gas introduction pipe 7, and the vacuum exhaust capacity is adjusted to control the pressure optimal for the process.

  After the above process start conditions are satisfied, first, plasma 9 is ignited by supplying predetermined power from the first high-frequency power source 4. At this time, the matching operation start point is optimized using a preset function in advance so that the operation of the matching unit 28 is stable and the time during which the reflected wave from the antenna 2 is sufficiently small is minimized. After the operation of the matching unit 28 is stabilized and the ignition of the plasma 9 is confirmed, predetermined power is supplied from the second high frequency power source 21 and the third high frequency power source 25, respectively. As described above, after the ignition of the plasma 9 is confirmed, the power is supplied from the second high-frequency power source 21 and the third high-frequency power source 25 because the load impedance is high in the absence of plasma, so that the antenna 2 and the processing substrate 12 are supplied. This is because there is a high possibility that a high voltage will be generated and an abnormal discharge or device malfunction due to noise will occur. The power application start timings of the second high frequency power supply 21 and the third high frequency power supply 25 are preferably simultaneous. This shortens the processing time of the processing substrate 12 by shortening the rising operation time of the first, second, and third high-frequency power supplies, and the processing substrate 12 within the rising time of the high-frequency power supply (that is, before the start of the process). At the same time that the reaction product from the plasma is deposited on the processing substrate 12 and the effect of applying the phase-controlled bias is minimized. It aims to be realized from.

  When the second high-frequency power source 21 and the third high-frequency power source 25 are turned on simultaneously, the matching operations of the matching units 20 and 24 affect the matching operations, and the matching operation time may be prolonged. This corresponds to the case where the plasma characteristics, that is, the load impedance of the high-frequency power source is greatly changed by the matching operation. In this case, it is necessary to shift the power supply start timings of the second high frequency power supply 21 and the third high frequency power supply 25. In this case, priority is given to the start of power supply of the second high-frequency power source 21 that applies a bias to the processing substrate 12. This is because priority is given to reducing damage to the processing substrate 12 and processing itself.

  At the start of power application of the second high-frequency power source 21 and the third high-frequency power source 25 described above, the phase controller 26 does not perform phase control but fixes the phase angle to a predetermined value in the preset mode. This is because the phase angle changes greatly during the matching operation of the matching units 20 and 24, and there is no guarantee that correct phase control operation can be performed even if phase control is performed during the matching operation. Of course, in order to minimize the time from the start of operation of the matching units 20 and 24 to the stabilization, the matching start position of each matching unit must be optimized using a preset function.

  The phase controller 26 starts phase control after confirming that the power application of the high-frequency power supply is stabilized, that is, after confirming that the matching operation of the matching units 20 and 24 is stable. In order to perform a stable phase control operation, the phase angle in the preset mode is fixed to a desired phase angle measured in advance. By adopting the above sequence, the start-up of the high-frequency power source and the phase control operation can be minimized, and the processing of the processing substrate 12 can be started quickly.

After the start of processing, the phase controller 26 obtains Vdc, Vpp, and V0p of the antenna 2 from the high voltage probe 31, and starts phase control based on a predetermined rule.
In order to minimize damage to the processing substrate 12 during processing, it is ideal to set the phase difference between the antenna 2 and the high-frequency electrode of the electrode 14 to 180 ° as described above. As a rule of the phase control method for maintaining this state, several methods can be considered.

  First, the control unit calculates the ratio of Vdc and Vpp (Vdc / Vpp value) in real time for the signal input from the high voltage probe 31, and sets the second value so that this value becomes the minimum value. That is, the phase output of the high frequency power supply 21 and the third high frequency power supply 25 is adjusted while being varied. By controlling the output to the second high frequency power supply 21 and the third high frequency power supply 25 so that the Vdc / Vpp value is always minimized, the phase difference between the high frequency electrodes of the antenna 2 and the electrode 14 is maintained at 180 °. Controlled.

  Second, the correlation data of the phase and Vdc / Vpp is stored in advance as a database on the apparatus side, and based on the data, the second high frequency power source 21 and the second high frequency power supply 21 are set so as to be the lowest value of Vdc / Vpp. 3 output to the high frequency power supply 25. The database is, for example, data as shown in FIG. When the high voltage probe 31 is connected to the antenna 2, the correlation data of Vdc / Vpp measured with the antenna 2 and the phase are stored, and when the high voltage probe 31 is connected to the electrode 14, the measurement is performed with the electrode 14. Vdc / Vpp and phase correlation data are stored.

  For example, when the high voltage probe 31 is connected to the antenna 2 as shown in FIG. 1, the control is based on the correlation data of Vdc / Vpp and phase measured by the antenna 2 shown in FIG. In the data, the minimum value of Vdc / Vpp is about -0.42. Therefore, in order to set the potentials of the upper and lower electrodes, that is, the antenna 2 and the electrode 14 in opposite phases (phase difference is 180 °), the second high-frequency power source 21 and the second high-frequency power source 21 are set so that Vdc / Vpp becomes −0.42. The output to the third high frequency power supply 25 is adjusted. By doing so, the phase difference between the high-frequency voltages applied to the antenna 2 and the electrode 14 can be controlled without directly measuring the phase.

Third, in addition to Vdc / Vpp, phase control can be performed from the absolute value of Vdc or V0p. As described above, Vdc takes a maximum value when the phase difference between the antenna 2 and the electrode 14 is 180 °, and takes a minimum value when the phase difference is 0 °. Conversely, V0p is minimum when the phase difference between the antenna 2 and the electrode 14 is 180 °, and Vdc is maximum when the phase difference is 0 °. Therefore, the output to the second high-frequency power supply 21 and the third high-frequency power supply 25 is adjusted so that the maximum value of Vdc or the minimum value of V0p is obtained in real time, similarly to the control using Vdc / Vpp. Thus, processing with a phase difference of 180 ° is possible. Note that when the absolute value of Vdc is the maximum and the absolute value of V0p is the minimum in real time, the responsiveness may have to be sacrificed to simply determine the minimum and maximum. As a realistic configuration in this case, a method of improving the responsiveness by giving a preset in advance and starting control from the vicinity of a predetermined position is desirable.
In addition, correlation data between the magnitude and phase of Vdc or V0p may be stored in advance, and output to the second high frequency power supply 21 and the third high frequency power supply 25 that are maximized or minimized may be performed.

In the second embodiment of the present invention, the high frequency voltage is not a high voltage probe 31 connected to the antenna 2 (or the electrode 14), but a position between the matching device 24 of the third high frequency power supply 25 and the mixer 27. Measured in The schematic sectional drawing of the present Example 2 of FIG. 6 is shown.
The configuration of the second embodiment makes use of the feature of the present invention that the phase control is performed by detecting the transition of the absolute value of the high-frequency voltage such as Vpp, Vdc, and V0p without directly detecting the phase information. is there.

The phase control in the second embodiment is limited to the case where the correlation between the high frequency voltage measured by the antenna 2 and the high frequency voltage measured by the matching unit 24 is confirmed in advance. Therefore, for example, in addition to the correlation data between the high-frequency voltage measured by the antenna 2 as shown in FIG. 5 and the phase difference between the upper and lower electrodes, the correlation data between the high-frequency voltage measured by the matching unit 24 and the phase difference between the upper and lower electrodes is acquired. In addition, it is confirmed how much deviation has occurred between them.
When actually performing the processing, the high frequency voltage extracted at the output unit of the matching unit 24 is guided to the phase controller 26, Vpp, Vdc, V0p are detected, and the above phase shift information is taken into account. As in Example 1, output to the second high-frequency power source 21 and the third high-frequency power source 25 is performed.
In the second embodiment, it is not necessary to provide detection means such as the high voltage probe 31, and the present invention can be implemented with a simple device configuration.

In the first embodiment, an example is shown in which the phase difference of the high-frequency voltage applied to the upper and lower electrodes is controlled to 180 ° in order to reduce damage to the processing substrate 12 as much as possible.
In the third embodiment, unlike the first embodiment, the phase difference of the high frequency voltage applied to the upper and lower electrodes reversely uses the damage given to the inside of the vacuum vessel.
Specifically, in the third embodiment, the phase difference is controlled so that the plasma space potential (Vs) is maximized when the processing substrate 12 is not processed. That is, control is performed so that the phase difference between the upper and lower electrodes is 0 ° or in the vicinity thereof. The same apparatus configuration as that shown in the first and second embodiments can be used. The detection parameters used are the same, and Vdc / Vpp, Vdc absolute value, or V0p absolute value is used.
As control targets, the phase is controlled so that the absolute values of Vdc / Vpp and Vdc are minimum and the absolute value of V0p is maximum. Further, when the control is performed using the known correlation data as shown in FIG. 5, for example, if Vdc / Vpp, the control is performed to be −0.1 or more. By performing such control, the plasma space potential (Vs) can be maximized, and the attached foreign matter can be plasma cleaned by damaging the wall in the vacuum vessel.

It is a schematic sectional drawing which shows the whole structure of the plasma processing apparatus of Example 1. FIG. It is a graph which shows the relationship between a high frequency electric potential, plasma space electric potential, and a sheath voltage. It is a graph which shows the characteristic of the voltage and phase detected with the upper and lower electrodes and each matching device. 3 is a schematic block diagram of a phase controller 26. FIG. 5 is a graph showing correlation data between Vdc / Vpp and phase measured by an antenna 2 or an electrode 14. It is a schematic sectional drawing which shows the whole structure of the plasma processing apparatus of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Antenna 3 Shower plate 4 1st high frequency power supply 5 Shower plate support flange 6 Antenna support flange 7 Process gas introduction pipe 8 Magnet (electromagnet)
9 Plasma 10 Exhaust Duct 11 Vacuum Exhaust Device 12 Processing Substrate (Wafer)
13 Focus ring 14 Electrode (processing electrode)
15 Refrigerant groove 16 Susceptor 17 Insulation base 18 Electrode base flange
DESCRIPTION OF SYMBOLS 19 Insulation tube 20 Matching device 21 2nd high frequency power supply 22 Choke coil 23 DC power supply 24 Matching device 25 3rd high frequency power supply 26 Phase controller 27 Mixer 28 Matching device 29 Transmitter 30 Oscillator 31 High voltage probe

Claims (6)

  A vacuum vessel in which plasma is generated in the vessel, a first high-frequency power source, a second high-frequency power source and a third high-frequency power source provided outside the vacuum vessel, and a first high-frequency power source from the first high-frequency power source A first electrode provided in or outside the vacuum vessel to which a voltage and a third high-frequency voltage from the third high-frequency power source are supplied, and a sample placed on the upper surface, the second high-frequency power source A second electrode provided in the vacuum vessel to which the second high-frequency voltage from the second high-frequency voltage is supplied and a signal obtained by measuring the high-frequency voltage of the first electrode or the second electrode. And a phase control device that controls a phase difference between the voltage and the third high-frequency voltage. The plasma processing apparatus according to claim 1,
A plasma processing apparatus, wherein a high voltage probe is provided as means for directly measuring the high-frequency voltage of the first electrode or the second electrode, and the phase difference is controlled using the output of the high voltage probe. A vacuum vessel in which plasma is generated in the vessel, a first high-frequency power source, a second high-frequency power source and a third high-frequency power source provided outside the vacuum vessel, and a first high-frequency power source from the first high-frequency power source A first electrode provided in or outside the vacuum vessel to which a voltage and a third high-frequency voltage from the third high-frequency power source are supplied, and a sample placed on the upper surface, the second high-frequency power source A second electrode provided in the vacuum vessel to which the second high-frequency voltage from is supplied, a mixer for mixing the first high-frequency voltage and the third high-frequency voltage, and the first power source A first matching unit provided between the mixers, a second matching unit provided between the second power source and the second electrode, and a third matching unit provided between the third power source and the mixer. And a third matching device,
A plasma processing apparatus that controls a phase difference between the second and third high-frequency voltages using an output signal of a high-frequency voltage from the third matching unit to the mixer. A vacuum vessel in which plasma is generated in the vessel, a first high-frequency power source, a second high-frequency power source and a third high-frequency power source provided outside the vacuum vessel, and a first high-frequency power source from the first high-frequency power source A first electrode provided in or outside the vacuum vessel to which a voltage and a third high-frequency voltage from the third high-frequency power source are supplied, and a sample placed on the upper surface, the second high-frequency power source A second electrode provided in the vacuum vessel to which a second high-frequency voltage from the first electrode is supplied; detection means for detecting a high-frequency voltage of the first electrode or the second electrode; and the second and third A control method of a plasma control device comprising a control means for controlling the high frequency voltage of
A plasma processing apparatus comprising: detecting a high-frequency voltage of the first electrode or the second electrode from the detection means; and controlling a phase difference between the second high-frequency voltage and the third high-frequency voltage. Control method. A vacuum vessel in which plasma is generated in the vessel, a first high-frequency power source, a second high-frequency power source and a third high-frequency power source provided outside the vacuum vessel, and a first high-frequency power source from the first high-frequency power source A first electrode provided in or outside the vacuum vessel to which a voltage and a third high-frequency voltage from the third high-frequency power source are supplied, and a sample placed on the upper surface, the second high-frequency power source A second electrode provided in the vacuum vessel to which the second high-frequency voltage from is supplied, a mixer for mixing the first high-frequency voltage and the third high-frequency voltage, and the first power source A first matching unit provided between the mixers, a second matching unit provided between the second power source and the second electrode, and a third matching unit provided between the third power source and the mixer. And a third control unit of the plasma control device comprising
A method for controlling a plasma processing apparatus, comprising: controlling a phase difference between the second and third high-frequency voltages using an output signal of a high-frequency voltage from the third matching unit to the mixer. In the control method of the plasma processing apparatus of Claim 4 and 5,
A plasma characterized in that any one of a peak-to-peak voltage Vpp, a self-bias voltage Vdc, and a maximum value of plasma space potential V0p is used as an index of phase difference control as an output of a high-frequency voltage used for the phase difference control. A method for controlling a processing apparatus.

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