JPH10242128A - Plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment good in reproducibility by switching a high frequency power from an r-f const. control to a Vpp-const. control according to the progress of the etching and etching after switching from the Vpp const. control to the r-f const. control for determining the end point of the etching. SOLUTION: In the initial stage a controller 41 sends a control system signal 102 to switch a high frequency power to an r-f const. control and outputs a signal for obtaining specified r-f power with an output setting signal 101. During etching, the controller 41 reads a Vpp voltage value and changes the output of the setting signal 101 to provide an output value corresponding to the Vpp voltage value for the Vpp const. control and switches from the r-f const. control to the Vpp const. control with the control system switching signal 102. At the etching end point determination, it changes the output of the setting signal 101 to an output value corresponding to a target r-f power value in the r-f const. control and switches from the Vpp const. control to the r-f const. control with the switching signal 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma processing method, and more particularly to a plasma processing method suitable for etching a sample such as a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, as a method of controlling the Vpp voltage to be constant, for example, as described in Japanese Patent Application Laid-Open No. Hei 5-234955 or Japanese Patent Application Laid-Open No. 8-199378, the Vpp voltage is kept constant. The power supply is controlled so as to keep the etching rate constant, so that the etching rate of the sample can always be kept constant.

[0003]

In a plasma for manufacturing semiconductors corresponding to a submicron, when the RF power is constant, for example, in an object to be processed in which different films to be etched are stacked, depending on the laminated film, an etching process may be performed. In some cases, the Vpp voltage greatly changes during the processing of the processing object as the processing proceeds. In addition, when an additional etching (or over-etching) process is performed to uniformly etch a film to be etched or to remove a residue, a Vpp voltage different from that during the etching process may be required.

In such a case, if the RF power, which is the output of the high frequency power supply, is controlled so that the Vpp voltage is constant, the RF power may be excessively supplied or insufficiently supplied depending on the processing state, and the etching performance may be reduced. In particular, there is a problem that shape control becomes impossible.

In Japanese Patent Application Laid-Open No. 8-199378, the magnetic field in the processing chamber is controlled to keep the Vpp voltage constant. However, there is a problem that the plasma is not stabilized by changing the magnetic field. Further, in Japanese Patent Application Laid-Open No. 8-199378, Vpp is kept constant even when the state of the plasma changes, such as during the additional etching process, so that there is a problem that excess or deficiency of the RF power occurs.

An object of the present invention is to provide a plasma processing having good reproducibility even when there is a change in the plasma state in the course of the plasma processing, a change over time due to the plasma processing, or a difference in processing equipment between the plasma processing. An object of the present invention is to provide a plasma processing method that can be performed.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide a plasma processing method for generating plasma in a processing chamber and applying high frequency power to a sample stage to etch a sample. Switching high frequency power from RF constant control to Vpp constant control,
When determining the end point of the etching process, Vpp constant control
This is achieved by switching to F constant control and etching the sample.

[0008] Another object of the present invention is to provide a plasma processing method for etching a sample using plasma generated in a processing chamber, wherein the removal of a natural oxide film on the surface of the sample when the plasma is unstable at the beginning of the etching and at the beginning of the etching. The constant voltage control is performed, and the etching process of the sample film to be etched is performed with the constant Vpp control. When the end point of the etching process of the film to be etched is determined, the control is switched to the constant RF power control after a lapse of a predetermined time from the start of the constant Vpp control. This is achieved by performing the etching end point determination of the etching film and the additional etching after the etching end point determination with the constant RF voltage control.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention switches a feedback factor in feedback control of a high-frequency power supply to either RF power or Vpp voltage in accordance with the progress of plasma processing, thereby causing a constant RF power to be supplied to plasma. Or by making the Vpp voltage constant. Hereinafter, control when the feedback factor is RF power is referred to as RF constant control, and control when the feedback factor is Vpp voltage is referred to as Vpp constant control.

[0010] An example of switching the feedback factor in the case of reducing the variation of the additional etching processing time in the plasma processing, for example, the etching processing to reduce the variation of the etching shape will be described below. (1) The plasma is not stable in the initial state where the plasma is generated. In such a case, if the Vpp constant control is performed, the RF power greatly changes because the plasma is unstable. In order to prevent this, the control is switched to the constant RF control, and a setting is made so that a constant RF power is supplied to the plasma. By doing so, it is possible to supply RF power without excess or shortage at the beginning of etching. (2) After a while, the plasma becomes stable. At this time, the plasma impedance gradually changes as the etching progresses. If the RF impedance is constantly controlled when the plasma impedance gradually changes, V
The pp voltage fluctuates. Therefore, the etching rate is Vp
It changes in proportion to the p voltage. When the Vpp voltage changes, the etching rate varies, and the etching time changes. If the additional etching time for removing the residue is determined by the ratio to the etching time, a change in the etching time causes a change in the additional etching time, making it impossible to obtain an etching shape with good reproducibility. Here, the etching rate can be made constant by switching the feedback factor to Vpp constant control. Thereby, the etching time and the additional etching time can be made constant.

As described above, the initial stage is an RF constant control,
By switching to Vpp constant control during the etching process, it becomes possible to control the etching shape. As another event, when processing multiple samples continuously,
The state of the plasma may change due to the influence of deposition or the like. Therefore, if the etching process is performed only by the constant RF control, the Vpp voltage changes according to the change in the state of the plasma, and the etching rate changes. Even in such a case, the Vpp constant control can always keep the etching rate constant and control the etching shape.

As described above, when switching the feedback factor from the RF power to the Vpp voltage, the continuity of the Vpp voltage is maintained. The following method is used to maintain the continuity of the Vpp voltage. (1) The Vpp voltage immediately before switching from the constant RF control to the constant Vpp control is stored. (2) A value corresponding to the stored Vpp voltage is output to the output setting signal. The output is switched from the RF constant control to the Vpp constant control at substantially the same time as the output setting. By performing such control, continuity of the Vpp voltage can be ensured. Also, when switching the feedback factor from the Vpp voltage to the RF power, the continuity of the RF power can be ensured in the same manner as described above, and the following method is employed to maintain the continuity of the RF power. (1) The RF power immediately before switching from the constant Vpp control to the constant RF control is stored. (2) Output a value corresponding to the stored RF power to the output setting signal. At the same time as the setting of this output, the control is switched from the Vpp constant control to the RF constant control. Thereby, continuity of RF power can be ensured.

In the case of Vpp constant control, when the plasma changes, the Vpp voltage is controlled to be constant by changing the RF power. At this time, the plasma may change significantly for some reason, and the Vpp voltage may be kept constant by supplying RF power that is higher than expected or lower than expected. By detecting these unexpected changes, abnormalities in the plasma processing can be determined, and abnormal plasma processing can be prevented. When the conditions for performing the etching are determined in the same manner as described above, the Vpp voltage range or the RF power range that can be regarded as normal is determined in advance. Vpp that can be considered normal
Let the voltage range be the Vpp voltage normal range. When etching is performed with constant RF control, Vp is always set during the etching process.
The p voltage is monitored to determine whether the voltage is within the Vpp voltage normal range. If the Vpp voltage is out of the normal range of the Vpp voltage, a warning is issued that the Vpp voltage is abnormal. It is possible to know from the alarm that an abnormality has occurred in the etching process. The above describes the normal range of the Vpp voltage in the constant RF control. Similarly, the normal range of the RF power is also set in the constant Vpp control,
An alarm can also be issued for RF power anomalies.

Next, a method of switching the feedback factor will be described. For the high-frequency power generation source, an output setting signal for setting RF power and Vpp voltage to be controlled from the outside and a feedback switching signal for switching a feedback factor are supplied. The output setting signal is set so that both RF power and Vpp voltage can be set with one signal, and whether the output setting signal sets RF power or Vp
The determination as to whether it means the p voltage is made based on the feedback switching signal. As another method of switching the feedback, there is a method of providing a predetermined threshold value to the output setting signal. The determination result of the magnitude of the output setting signal with respect to this threshold value is used as a feedback switching signal. According to this method, the feedback factor can be switched only by the output setting signal without providing the feedback switching signal. This threshold may be current or voltage. The threshold may be set to any value as long as it is within a range in which the output setting signal can be output. In particular, by setting this threshold value to 0 V, the polarity of the voltage of the output setting signal is determined, and Vpp constant control and R
F constant control can be switched. Further, when the output setting signal is set near the threshold value, the switching of the feedback factor frequently occurs due to the influence of noise or the like. To prevent this phenomenon, frequent switching can be prevented by providing the threshold with hysteresis. Further, when the power of the high frequency power generation source is turned on, the switching of the feedback factor is set to Vp
It is also effective to perform an initial setting that is one of the constant p control and the constant RF control to prevent frequent switching operation of switching the feedback factor.

An embodiment of the plasma processing apparatus according to the present invention will be described below with reference to FIG. Sample table 1 in vacuum processing chamber 1a
The sample stage 1 is provided with a wafer 2 to be subjected to a plasma process, in this case, an etching process. An RF power supply 11 is provided as a high-frequency power generation source, and an output of the RF power supply 11 is connected to an RF detector 12 for detecting an incident wave power RF of the generated high-frequency power. RF detector 12
Are connected to the sample stage 1 via the matching box 14 in order to efficiently supply high frequency power to the sample stage.
The sample stage 1 is connected to a Vpp detector 13 for detecting a peak-to-peak voltage of a high-frequency voltage generated by high-frequency power. An output control signal 104 is input to the RF power supply 11 from the error amplifier 31, and the RF power supply 11 generates high-frequency power in proportion to the output control signal 104. Error amplifier 31
The output setting signal 101 from the control device 41 and the feedback signal 10 selected by the feedback switch 21
3 is input. The error amplifier 31 outputs the output setting signal 101
And the feedback signal 103 and output setting signal 1
An output control signal 104 is output so that an error between the output signal 01 and the feedback signal 103 is eliminated. The output of the RF detector 12 amplified by the RF detection signal amplifier 22 and the output of the Vpp detector 13 amplified by the Vpp detection signal amplifier 23 are connected to the feedback switch 21. Further, the feedback switch 21 selects one of the output of the RF detection signal amplifier 22 and the output of the Vpp detection signal amplifier 23 according to the control method switching signal 102 from the control device 41 and outputs the selected signal as the feedback signal 103. The control device 41 outputs an output setting signal 101 and a control method switching signal 102 to the error amplifier 31. Also,
An RF monitor signal 105 in which the output of the RF detector 12 is amplified by the RF detection signal amplifier 24 and a Vpp monitor signal 106 in which the output of the Vpp detector 13 is amplified by the Vpp detection signal amplifier 25 are input. Is programmed so that it can be stored. The control device 41 is programmed so as to be able to set and store a plurality of RF power target values, RF power dead zones, RF power normal ranges, Vpp power target values, Vpp power dead zones, and Vpp power normal ranges. ing. During the etching process, the output setting signal 101 and the control method 102 are output from the control device 41, and the RF monitor signal 105 and the Vpp monitor signal 106 are always stored.

FIG. 2 shows an example of the change over time of the Vpp voltage when the etching process is performed under the constant RF control in the apparatus configuration shown in FIG. The solid line 201 in FIG. 2 is a time change of the Vpp voltage when the first sample is processed, and etching is started at time T0, time T11 is an etching end point time, and time T11 to time T12 is additional etching processing. is there. A broken line 202 is, for example, a time change of the Vpp voltage when the 25th sample is processed. Etching is started at time T0, time T21 is an etching end point time, and time T21 to time T22 is additional etching processing. As shown in FIG. 2, the Vpp of the 25th sheet is smaller than that of the first sheet.
The voltage has decreased, and the etching time has increased. Due to the long etching time, a difference occurs in the etching shape between the first sheet and the 25th sheet. The etching end point time T11 / T21 and the etching completion time T12
T22 is an end point determination method such as emission spectroscopy, which is performed by the controller 4
1 is the time determined.

Next, the same sample as in the case of changing the Vpp voltage as shown in FIG. 2 was used when the RF processing was constant at the start of the etching process, then Vpp constant control, and the additional etching process time was the RF constant control. 3 is shown in FIG. FIG.
The time T0 is an etching start time, and the time T31 is an etching processing initial time preset in the control device 41, and a time that does not affect the progress of the etching processing is selected. Time T41 is the etching end point time, time T51 is the etching completion time, and time T4
The control device 41 also determines 1 and the time T51. FIG.
In (a), the time change of the Vpp voltage of the first sample is shown by a solid line 203, and the time change of the 25th sample is shown by a broken line 204. From time T31 to time T51, the solid line 203 and the broken line 204 almost overlap. In FIG. 3B, the time change of the RF power of the first sample is shown by a solid line 205, and the time change of the 25th sample is shown by a dashed line 206.
And the broken line 206 overlap. In FIG. 3C, the time change of the set value of the output setting signal 101 of the first sheet is represented by a solid line 207a.
The time change of the 25th sheet is indicated by a broken line 2 in 207b and 207c.
08a, 208b, and 208c. In the period from time T0 to time T31, the solid line 207a and the broken line 208a overlap. In the period from time T31 to time T41, the solid line 207b and the broken line 208b overlap. During the period from time T41 to time T51, the solid line 207c and the broken line 208c do not overlap. In addition, Vpp voltage and R
F power is Vpp monitor signal 106 and RF monitor signal 10
5 is always stored in the control device 41.

In the first sample, the controller 41
Is switched to constant RF control by the control method signal 102, and a signal for outputting predetermined RF power is output by the output setting signal 101, that is, an output value corresponding to the target RF voltage value at the start of discharge. As a result, the power of the target RF power value is applied to the sample stage from the RF power supply 11, and a predetermined etching process is started from time T0. Therefore, FIG.
As shown in (c), the output setting signal 101 during the period from time T0 to time T31 is as shown by a solid line 207a. The control device 41 reads the Vpp voltage value Vppa immediately before the time T31, and outputs the output of the output setting signal 101 to Vpp constant control so that the Vpp voltage value Vppa at this time is used to perform Vpp constant control.
The output value is changed to the output value corresponding to the voltage value Vppa, and at the same time, the control method switching signal 102 is used to switch from the constant RF control to the constant Vpp control. At this time, the Vpp voltage value Vppa is stored in the control device 41. Thereby, the RF power supply 11
After that, power at which the Vpp voltage value becomes Vppa is applied to the sample stage, and the etching process in which the Vpp voltage is kept constant starts from time T31. Therefore, as shown in FIG. 3C, the output setting signal 101 in the period from the time T31 to the time T41 becomes a solid line 207b. Thereafter, the control device 41 determines the etching end point time T41. Simultaneously with the determination of T41, the control device 41 reads the PF monitor signal 105, and changes the output of the output setting signal 101 to the target RF power value of the constant RF control so as to perform the constant RF control at the RF power value RFa at this time. The output value is changed, and at the same time, the control is switched from the constant Vpp control to the constant RF control by the control method switching signal 102. As a result, the power of the RF power value RFa is applied from the RF power source 11 to the sample stage, and the additional etching process is started from time T41. Therefore, FIG.
As shown in the figure, the output setting signal 101 during the period from the time T41 to the time T51 is as shown by a solid line 207c. In addition, in the additional etching in this case, the RF power is increased in the same manner as during the etching so as to increase the incident energy of the ions in the plasma in order to remove residues during the etching. In addition, in the additional etching, when over-etching is performed with less damage, the RF power may be set low. Thereafter, the time T41 is set as a time of a predetermined ratio with respect to the required time from the time T31 to the time T41.
From time to time 51, additional etching processing is performed, and the etching processing is completed at time T51.

The twenty-fifth sample has a Vp value as shown in FIG.
The p voltage tends to decrease. The case of the twenty-fifth sample that tends to be shown in FIG. 2 will be described below. The etching starts at time T0, but the Vpp voltage becomes lower as shown by the broken line 204 as shown in FIG. At time T31, the control device 41 outputs the Vpp voltage value Vpp.
The control is switched to the constant Vpp control so as to be a. Time T3
Since the RF power is controlled so that the Vpp voltage becomes Vppa after 1, the RF power changes as shown by a broken line 206 larger than the solid line 205 as shown in FIG. From time T31 to time T41, the Vpp voltage is 25 for the first sheet.
Since the first sheet is the same, the progress of etching is 2 for the first sheet.
The fifth wafer is the same, and the etching end point time of the twenty-fifth wafer is the same time T41 as the first wafer. Further, as shown in FIG. 3C, the output setting signal 101 changes from time T0 to time T3.
With the RF constant control of 1, the 25th sheet has the same set value as the first sheet,
That is, the same broken line 208a as the solid line 207a is output,
In the constant Vpp control from time T31 to time T41, the 25th sheet outputs the same set value as the first sheet, that is, the same broken line 208b as the solid line 207b. Therefore, the solid line 207a
And a broken line 208a, and a solid line 207b and a broken line 208b.
Overlap in FIG. 3 (c).

At time T41, as in the first sheet, the control device 41 reads the RF monitor signal 105, and at this time R
The output of the output setting signal 101 is changed so as to perform the RF constant control at the F power value RFb, and at the same time, the control mode switching signal 1
In 02, the control is switched from the constant Vpp control to the constant RF control.
As a result, the power of the RF power value RFb is applied to the sample stage from the RF power supply 11, and the additional etching process is started from time T41. Therefore, as shown in FIG. 3C, the output setting signal 101 in the period from the time T41 to the time T51.
Becomes like a broken line 208c. In this case, the broken line 2
Since 08c is for the 25th processing, it is necessary to make the RF power value RFb higher than the RF power value RFa of the first processing in order to perform additional etching processing under the same conditions as the first processing. As the output setting signal 101 for the processing on the 25th sheet, a setting signal higher than the solid line 207c is output as indicated by a broken line 208c. Thereafter, additional etching is performed for a period of time T41 to time 51 as a predetermined ratio of time to the required time of time T31 to T41, and the etching is completed at time T51. The additional etching processing time of the 25th sheet is the same as that of the first sheet from time T31 to time T41 by the Vpp constant control,
Therefore, the time T41, which is the additional etching processing time,
And the period of time T51 is the same as the first sheet.

Next, a case where the film to be etched is a multilayer film will be described with reference to FIG. FIG. 6 shows a usage example in consideration of an actual etching process. FIG. 6 shows an example of a four-step recipe. FIG. 6 shows Steps 1 to 4 constituting an actual etching process at the time of ignition (at the time of plasma generation), which is a plasma generation process after the start of the process. In step 1, RF constant control is performed and is indicated by RF1, and in step 2, Vpp constant control is performed and Vpp2
In step 3, Vpp constant control is performed and Vp
When the end point is determined in step 3, the constant RF control is performed and is indicated by RF3. In step 4, the constant RF control is performed and indicated by RF4. Step 1 is for removing a film (for example, a natural oxide film) on the wafer surface, and the constant RF control (RF1) is used because even if Vpp fluctuates a little, there is no significant effect on the etching.
Step 2 is for etching the first layer film. As shown in FIG. 3, Vpp constant control (Vpp2) is used to ensure the reproducibility of the etching process. Step 3 is for etching the second layer film, and is performed with Vpp constant control (Vpp3) as in step 2. In this case, the set value of the Vpp voltage for constant control of the first layer and the second layer may be changed in accordance with the optimum conditions of each layer. Further, a change in the Vpp set voltage value between the first layer and the second layer can be detected by measuring the amount of light emission of a specific wavelength using emission spectroscopy. When the end point is determined in step 3, the plasma state changes largely near the end point detection, and there is a possibility that the fluctuation range of Vpp becomes large. As described above, near the end point detection, Vp
Since the use of the constant p control may greatly change the plasma state, the constant RF control is used. That is, as shown in FIG. 4, after step 3 is started, the Vpp constant control (Vpp
3) is performed, and then the RF constant control (RF3) is performed until the end of step 3. The transition from the constant Vpp control to the constant RF control is performed by reading the RF monitor signal when the dead time has elapsed and outputting the RF power corresponding to the read RF monitor signal. Step 4 is, for example, a step for additional etching whose time is determined by the time of step 3,
In this step, the RF constant control (RF4) is performed so as not to be affected by the plasma state fluctuation due to the progress of the degree of exposure of the base film. In this case, additional etching is performed to eliminate the etching residue in the surface of the wafer as a sample, and the RF power is reduced so as to reduce the incident energy of ions in the plasma to the wafer and to suppress damage to the base. I have.

In FIG. 4, an allowable range is set for each step of Vpp and RF incidence. In this case, Vp
The upper limit error line is VL for each step of p
1U, VL2U, VL3U, and VL4U, and the lower limit error lines are VL1D, VL2D, and VL3, respectively.
D, VL4D. Also, the upper limit error lines are FL1U, F1
L2U, FL3U, and FL4U are set, and the lower error lines are FL1D, FL2D, FL3D, and FL, respectively.
4D is set. In each of these steps of Vpp and RF injection, an abnormality is detected when the Vpp voltage or the RF power sometimes exceeds the upper or lower error line.

As described above, according to this embodiment, the fluctuations of the Vpp voltage and the RF power can be arbitrarily controlled during the plasma processing such as the etching processing, so that the etching shape can be controlled with good reproducibility. . Similarly, even if the plasma state changes due to a temporal change due to the plasma processing or a machine difference between the processing apparatuses, the Vpp voltage or R
Since the F power can be controlled to be constant at an arbitrary value, plasma processing can be performed on a plurality of samples under the same conditions, and plasma processing with good reproducibility can be performed.

Although the present embodiment has described the high-frequency power source applied to the sample stage for processing the sample separately from the plasma source, the same control method is applied to the high-frequency power source for plasma generation and the DC power source. It can also be implemented for power sources. Further, the Vpp voltage is related to the plasma sheath voltage VF. Therefore, instead of Vpp constant control, VF constant control for keeping the VF voltage constant and RF
Switching of constant control can also be easily realized, and Vp
The constant p control can be defined as a control including the constant VF control.

In this embodiment, the etching process has been described as a plasma process. However, in a process using a plasma such as a plasma CVD, the same control is performed when the plasma transitions from an unstable state to a stable state. What is necessary is just to perform, and it is not limited to an etching process.

[0026]

According to the present invention, in a processing apparatus using a plasma, a plasma processing with good reproducibility even when the plasma state changes during the plasma processing process, there is a temporal change due to the plasma processing, or there is a difference between the processing apparatuses. Is effective.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a plasma processing apparatus of the present invention.

FIG. 2 is a diagram illustrating a change in a Vpp voltage when plasma processing is performed with constant RF control in a plasma processing apparatus.

FIG. 3 is a diagram showing an example of switching between constant RF control and constant Vpp control in the apparatus of FIG. 1;

FIG. 4 is a diagram showing another example of switching between the constant RF control and the constant Vpp control in the apparatus of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample stand, 2 ... Sample, 11 ... RF power supply, 12 ... RF detector, 13 ... Vpp detector, 21 ... Feedback switcher, 31 ... Error amplifier, 41 ... Control device, 101 ... Output setting signal, 103 ... Feedback signal, 104: control output signal, 105: RF monitor signal, 106: Vpp monitor signal, 501: comparator, 502: threshold voltage.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsushi Ito 794, Higashi-Toyoi, Katsumatsu-shi, Kamamatsu, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. Kuno Engineering Corporation Kasado Office

Claims (5)

[Claims] 1. A plasma processing method for generating plasma in a processing chamber and applying high-frequency power to a sample stage to etch a sample, wherein the high-frequency power is controlled to a constant RF according to the progress of the etching process. A plasma processing method characterized by switching from Vpp constant control to Vpp constant control, and switching from Vpp constant control to RF constant control to determine the end point of the etching process. 2. A plasma processing method for generating plasma in a processing chamber and applying high-frequency power to a sample stage to etch a sample, the method comprising the steps of: The removal of the natural oxide film is performed by the constant RF voltage control, the etching of the sample to be etched is performed by the constant Vpp control, and the end point of the etching of the film to be etched is determined after a lapse of a predetermined time from the start of the constant Vpp control. A plasma processing method comprising: switching to constant RF power control; and performing the etching end point determination of the film to be etched and additional etching after the etching end point determination by performing constant RF voltage control. 3. The plasma processing method according to claim 2, wherein the film to be etched is a laminated film, and after a lapse of a predetermined time from the start of Vpp constant control of the lowermost layer of the laminated film.
A plasma processing method for switching to F power constant control. 4. A plasma processing method according to claim 2, wherein said film to be etched is a laminated film, and a Vpp voltage setting value is changed according to each layer of said laminated film. 5. The plasma processing method according to claim 2, wherein said RF power does not fall within an RF power allowable range.
And a plasma processing method for outputting a signal for determining that the plasma processing is abnormal when the Vpp voltage does not fall within the Vpp voltage allowable range.