JP5210659B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus, and more particularly, to a plasma processing apparatus having an impedance matching device in a transmission path for applying a high-frequency bias power.

In the manufacturing process of a semiconductor element, various processes using plasma such as an etching process, an ashing process, and a CVD process are performed. In these processing apparatuses using plasma, the process gas is ionized and ionized to increase the reactivity with the material to be processed. In addition, for the purpose of improving the processing accuracy, the incident angle of the charged particles and the incident energy on the material to be processed are controlled by using the high frequency bias power, thereby improving the anisotropy of the processing.
The bias power source has a modulation function such as time modulation (Time Modulation = hereinafter referred to as TM modulation), AM modulation (Amplitude Modulation), or FM modulation (frequency Modulation) which is intermittently turned ON / OFF. When a high frequency power source is used, as shown in FIG. 2, processing is performed while changing the presence / absence of modulation, the modulation mode, the RF power, and the like according to the processing content. However, in such an apparatus, the transmission efficiency varies due to a switching operation between a continuous wave and a modulated wave of bias power, a variation in the magnitude of RF power, and the like.

  Further, in the RF sensor of the impedance matching device provided for controlling the residual reflected wave, controlling the impedance, phase, or peak-to-peak voltage (Vp-p) of the transmission circuit, the offset value of the detected signal is May fluctuate significantly. In such a case, the accuracy of impedance matching may be lowered, or the stability of control may be lowered and reproducibility may be deteriorated.

  Patent document 1 is known as an example of a plasma processing apparatus. The processing apparatus shown in this document includes a sample stage for holding a material to be processed in a vacuum vessel, and a high frequency power supply antenna for forming plasma on the material to be processed, and the formation and control thereof. The structure which has the air-core coil for carrying out in the outer peripheral part of a vacuum vessel is carried out.

  The high-frequency power supply antenna has a circular shape and is installed on the upper part of the material to be processed. A coaxial waveguide for supplying high-frequency power for generating plasma from a high-frequency power source is connected to the antenna above the workpiece. In addition, a bias power supply antenna is installed inside the sample stage installed in the lower part of the processing chamber, and the charged particles of the processing gas excited in the plasma are accelerated up to the material to be processed with arbitrary energy. A high-frequency power source for making incident while controlling directionality is connected.

  The high-frequency power supplied to the upper antenna electrode ionizes the processing gas supplied from the gas supply device into the vacuum vessel and turns it into plasma. At this time, the ionized process gas is confined by the magnetic field generated by the air-core coil in the outer peripheral portion of the vacuum vessel, and the shape, density and distribution of the plasma in the vacuum vessel are controlled to an arbitrary shape. Here, the electric field generated by the power of the high-frequency power source accelerates charged particles in the plasma toward the material to be processed, and processes the material to be processed while controlling the direction of movement and the incident energy.

Further, in such an apparatus, as an approach for improving the matching accuracy of the automatic matching device, a technique for improving the matching accuracy by correcting the preset position of the variable element by pre-discharge, the maximum value or the minimum value of the voltage Vp-p A technique for performing matching control as a reference is disclosed (see Patent Documents 2 and 3).
JP-A-4-69415 JP 2006-286306 A JP-A-9-134799

  In the conventional plasma etching apparatus, the deviation of the offset of the RF sensor due to the fluctuation of the RF power directly leads to a decrease in matching accuracy or a decrease in process reproducibility. In order to improve this, in many cases, a technique has been used in which the position of a variable element such as a variable capacitance or a variable inductance that changes impedance is moved to a position close to the matching position to some extent in advance.

  This method is an effective means if it is a single discharge with a certain power. However, in this method, when changing the RF power value, it is necessary to perform preliminary discharge, change the position of the variable element, and the like. That is, it has been difficult to apply to a process that requires continuous RF power value change while power supply is continued without interrupting the supply of RF power.

  When applying to a process, if the RF power supply is interrupted, the bias potential formed between the plasma and the material to be processed is lost, so contaminants and etchants in the processing chamber accumulate on the surface of the material to be processed. There are things to do.

  In addition, when the plasma is extinguished and ignited repeatedly, and when the bias potential is repeatedly applied and shut off, this repeated process, particularly abrupt fluctuations in the bias potential immediately after application of RF power, for example, overshoot, may cause the plasma. Instability increases.

  In many cases, such an unstable phenomenon occurs because a variable element cannot follow a rapid power change and impedance change immediately after application of RF power. In addition, a sensor called an RF sensor that monitors the impedance and phase of an RF power transmission system is affected by fluctuations in the RF power, and offset values such as the zero point shift, thereby monitoring stable impedance and phase. One of the causes is that it becomes difficult.

  Such a phenomenon is constituted by two or more different frequency components such as a modulated wave such as AM modulation, FM modulation, or TM modulation, as compared with a case of high frequency power constituted by one kind of frequency called a fundamental wave. Often, this is a problem with high frequency power. In particular, the influence of the modulated wave is very large on the stability degradation or reproducibility degradation of the matching operation due to the offset of the RF sensor.

  Further, in connection with matching control, there is a problem that Vp-p is not stable even if the RF power value is constant due to the difference in the minute structure of the processing chamber and the transmission path and the influence of assembly errors. This means that the process results and the ion sweep voltage from the plasma, which greatly affects the stability, are not stable. That is, in order to improve the stability and reproducibility of the processing result, not only the stability of the matching operation is improved, but also means for stabilizing the voltage Vp-p is required.

  The present invention has been made in view of these problems, and can improve the stability of the matching operation of the impedance matching device inserted in the transmission line to which the high-frequency bias power is applied, and can stabilize the processing result. A plasma processing apparatus is provided.

  In order to solve the above problems, the present invention employs the following means.

A vacuum vessel that houses an antenna electrode to which high-frequency power for plasma generation is supplied and a substrate electrode to which high-frequency bias power is supplied is provided, and a material to be processed placed on the substrate electrode is generated by the generated plasma. In a plasma processing apparatus that performs plasma processing, a high-frequency bias power source that supplies a high-frequency bias power to the substrate electrode is inserted into a transmission path that connects the substrate electrode, and the impedance of the transmission path as viewed from the high-frequency bias power source side is kept constant. An automatic impedance matching device is provided, and the automatic impedance matching device adjusts an impedance element constituting the matching device based on an output of an RF sensor that measures the impedance or phase of the transmission line as viewed from the high-frequency bias power source. And offset the offset of the RF sensor output during control. An offset correction unit is provided, and the offset correction unit divides the magnitude of input power input to the matching unit into multiple stages, and stores the offset correction value in advance for each of the multiple stages of input power. And an offset of the output of the RF sensor according to a correction value set in the storage device.

  Since the present invention has the above-described configuration, it is possible to improve the stability of the matching operation of the impedance matching device inserted in the transmission line to which the high-frequency bias power is applied, and to stabilize the processing result.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing a configuration of a plasma etching apparatus according to the present embodiment. This plasma etching apparatus is configured as an ECR plasma etching apparatus. A processing chamber is configured by providing an antenna electrode 105 that transmits power serving as an energy source of the plasma 104, a substrate electrode 109 that transmits bias power, and a gas supply device 111 that supplies processing gas in the vacuum chamber 101. .

  An air-core coil 106 for generating a magnetic field is disposed on the outer periphery of the vacuum vessel 101 so as to surround the processing chamber. An antenna electrode 105 for supplying electric power and a gas introduction plate 112 having a plurality of fine holes for introducing a processing gas from the gas supply device 111 into the vacuum container are installed on the upper part of the vacuum container 101. . Further, an evacuation device 113 (here, a turbo molecular pump) is connected to the vacuum vessel 101 in order to maintain a vacuum. The upper antenna electrode 105 has a function of supplying bias power for maintaining plasma in the processing chamber. The lower substrate electrode 109 has a function of supplying high-frequency power for generating an electric field perpendicular to the material 102 to be processed, and a stage for mounting the material 102 to be adsorbed and held by Coulomb force. It has a function.

  A coaxial waveguide 108 is connected to the upper antenna electrode 105 for connection to a magnetron 107 for supplying high-frequency power arranged outside the vacuum vessel 101. In the transmission line drawn out of the vacuum vessel by the coaxial waveguide 108, the magnetron 107 passes through an automatic matching unit 114 for absorbing the impedance fluctuation of the transmission line and the plasma 104, and an isolator 115 for absorbing the reflected power. Connected.

  A high-frequency power source 110 that supplies bias power to a substrate electrode 109 installed inside the sample stage 103 has an automatic matching unit 116 connected between the substrate electrode 109 and the high-frequency power source 110, and a transmission line. In addition, power can be supplied while absorbing the impedance fluctuation of the plasma 104. Further, a DC voltage source 117 for generating a Coulomb force for attracting and holding the workpiece 102 on the sample stage is connected to the substrate electrode 109 via a filter circuit 118.

  FIG. 2 is a diagram for explaining the automatic matching device. RF power output from the high frequency power supply 110 is input to the automatic matching unit 116 and input to the RF sensor 201. The RF sensor 201 extracts a part of the input electric power and converts it into a voltage and a current to detect the phase of the signal and the impedance of the transmission system. These detected signals are input to the A / D converter 202, quantized, and input to the control device 203 that controls the control.

  The control device 203 includes a CPU 204, a storage device 205, and an I / O device 206. The control device 203 drives the variable elements 207 and 208 based on the signal input from the A / D converter, and reduces the impedance of the transmission system. Control. Here, the control device 203 performs calculations necessary for controlling the pulse motors 209 and 210 to which the variable elements 207 and 208 are connected based on the input signal, and sends the control signal to the I / O device. To the motor controller 211.

  Further, the CPU 204 extracts a correction value necessary for correction of the RF sensor from the storage device 205 based on the magnitude of the separately detected RF power for the input signal, and performs offset correction of the detection value of the RF sensor. Run. At this time, in the example shown in the figure, the magnitude of the RF power is configured to be received from the high-frequency power supply 110 through the communication 212. However, a sensor for detecting the magnitude of the RF power is installed in the automatic matching unit. Also good.

  The control device 203 that has received the signal from the A / D converter 202 and the magnitude of the RF power through the communication 212 from the high-frequency power source performs offset correction of the RF sensor according to the processing flow shown in FIG. 3, and simultaneously performs matching control. .

  Immediately after applying the RF power, the automatic matching unit immediately starts the automatic matching operation by the communication 212 from the high frequency power supply 110. At this time, the magnitude of the applied RF power is detected by communication 212 from the high frequency power supply 110 (S301). Next, based on the magnitude of the detected RF power, among the correction database stored in the storage device 205, the RF power value is divided into multiple stages, and the identification code 302 corresponding to each zone is stored. A database (hereinafter referred to as a power zone determination data array) is referred to (S303), and an identification code 302 corresponding to the RF power is set (S304). Next, with reference to the set identification code 302, a database (hereinafter referred to as a correction value data array) storing offset correction values corresponding to each identification point is referred to (S305), and an offset correction amount 307 is extracted. Determine (S306). The power zone determination data array in step 303 has a format as shown in FIG. 4 and can list the relationship between the identification code and the RF power. The correction value data array 305 in step 305 has a format as shown in FIG. 5 and can list the relationship between identification codes and correction values. It should be noted that these formats are merely examples, and it goes without saying that other data formats may be adopted with the same storage contents depending on the processing method and operation. Further, in this example, each correction value of phase and impedance corresponds to one identification code, but other data such as the RF power value of the point at which the offset correction value is determined are also included. It may be stored.

  Next, the output value of the RF sensor 201 is collected via the A / D converter 202 (S308). For each of the collected phase and impedance values, the offset correction value 307 determined in (S306) is subtracted, and the difference is calculated (S309). The value obtained as a result is used as the detection value of the RF sensor to confirm the completion of the matching operation (S310). Here, the completion point of the matching operation is 50Ω (50 + j0) having a pure resistance value equal to the output impedance of the high-frequency power supply 110. In (S310), the pure resistance value is compared with the detected impedance, and the difference is calculated and whether the deviation direction is +/− with respect to the pure resistance value is calculated. If the difference is within the matching operation completion determination range value, the operation is completed, and the process returns to the collection of values from the RF sensor in (S308).

  Next, when it is determined in (S310) that the matching is incomplete, the current RF power is checked (S311). At this time, if there is a change in the RF power, the process is immediately interrupted, the RF power zone is determined again (S304), and the correction value is reset. If there is no change, the operating amount and operating speed of the variable element are calculated using the deviation direction and the difference calculated in (S310), and a command is given to the motor controller 209 (S312). At this time, since the matching control is feedback control that drives the variable element based on the detection value of the RF sensor, the processing system immediately returns to the data collection from the RF sensor in (S308) and performs the processing up to (S312). The process is repeated until the matching completion determination is made in (S310).

  The correction value determination process shown in (S303) and (S305) combines a zone determination and correction value extraction routine according to the RF power, and a correction value corresponding to the RF power is determined by a single determination. You may enable it to extract.

  Next, when the matching operation is completed and the RF power is being supplied, the RF power of the next step is set, and the supply of a different RF power value is started without interrupting the RF power from the high frequency power supply 110 Show about.

  The basic processing is the same as in the above operation example, but when the matching operation is completed and the loop operation is performed between the matching completion determination (S310) and the data collection from the RF sensor (S308), The setting value for 110 is changed, the RF power input to the automatic matching unit 116 is changed, and the matching determination (S310) that detects that the matching point is shifted is started as a trigger.

  In the matching determination (S310) where the incomplete matching is detected, the RF power confirmation (S311) is performed and compared with the previous value. If the difference is recognized, the RF power value is detected by communication 212 from the high frequency power supply 110, the RF power zone determination (S304) and the offset correction value are determined (S306), and the RF corresponding to the changed RF power is detected. Determine a new offset correction value for the sensor. Thereafter, data collection from the sensor (S308) is performed, the detection value of the RF sensor is calculated (S309), the RF sensor offset is corrected according to the RF power change, and then the matching completion confirmation (S310) is performed again. )I do. If incomplete matching is detected again, the RF power is confirmed (S311), and it is determined that there is no change in the RF power again, and then variable element control (S312) is performed.

  Here, an example of detection characteristics of the RF sensor is shown in FIG. This figure schematically shows the amount of change of the zero offset value with respect to the RF power in an RF sensor using a general electric field coupling and / or magnetic field coupling in combination. In this example, an arbitrary power value is set as a calibration point at only one point, and the offset is adjusted to be minimum at this point. This indicates that the sensor offset is almost zero at the RF power determined as the calibration point, that is, the most accurate detection is possible. It should be noted that the sensor offset increases when the RF power value increases or decreases with respect to the calibrated RF power. This is generally known to occur due to the characteristics of the sensor coupling method, and is unavoidable as a phenomenon.

  Therefore, in the present embodiment, using the database as shown in FIG. 4 and FIG. 5, this offset is divided into regions with arbitrary RF power values in multiple stages at division points 602 and 603, and the center points of the respective regions. A correction value that minimizes the offset is given at (adjustment point 601). As a result, the offset value change curve 604 can be suppressed to a certain value or less. At this time, an operation such as increasing the number of division points when the variation of the offset value is large or decreasing when the offset value is stable may be performed. In addition, the correction method is not only based on the center point of each region set in multiple stages, but also provides an offset correction value based on the start value or end value of each region. It is good to change arbitrarily according to. Even in this case, the change curve of the offset value can be suppressed within a certain range.

  By the way, in the above method, the offset value change curve 604 is obtained by adjusting an offset correction value to be given to an arbitrary RF power as a reference between division points that divide a region in multiple stages. The slope of the change curve 604, the rate of change, or the magnitude thereof can be changed.

  Here, in the sensor offset correction, the correction value is subtracted from the detection of the RF sensor in the processing routine (S309). If the correction value is not an appropriate value, the detection value of the RF sensor is shifted. It will be. That is, the matching point is shifted by the sensor offset, and a residual reflected wave is generated. By using this, the magnitude of the residual reflected wave at the completion of matching can be arbitrarily controlled. That is, the difference between the traveling wave power and the reflected wave power, that is, the magnitude of Vp-p whose value is determined by the effective power can be adjusted to an arbitrary value, and fine adjustment can be performed. As a result, it becomes possible to correct the deviation of Vp-p caused by the difference in the chamber structure and the difference in the minute characteristics of the transmission path, and it becomes possible to compensate for the decrease in stability or the error. The sensor offset correction value used at this time is stored in the correction value data array 305.

  Next, the construction of the power zone determination data array and the correction value data array will be described. This needs to be constructed prior to the processing of the workpiece. Although there are several construction methods, in this embodiment, the variation of the RF power value and the sensor offset is mapped using a test plasma that can include the impedance range of the plasma used in the processing of the material to be processed. The number of divisions of the correction range and the correction value are determined according to the amount.

  FIG. 7 is a diagram for explaining correction value data array creation processing. First, as shown in FIG. 9, the plasma impedance 801 of the process conditions scheduled to be operated by the apparatus is plotted on the Smith chart 803, and the impedance change range 802 that can sufficiently cover the range by changing the RF power is formulated. . Here, the impedance change range may define the maximum range of plasma that can be operated in the apparatus (S701, S702). Next, in order to evaluate the distribution of the offset value of the RF sensor in the established impedance change range 802, the RF power is changed from the minimum output to the maximum output in the uncorrected state, and the residual reflection at the time of no correction shown in FIG. A wave change curve 901 is created (S703). Next, in order to determine the number of divisions of the range, the threshold value 804 of the residual reflected wave to be suppressed is written in FIG. 9, and the division points 903 and 904 are set at the intersections with the change curve 901 of the residual reflected wave at the time of no correction. Setting is made (S704, S705).

  Next, in order to determine the offset correction value of the RF sensor, a reference RF power value is determined based on the previously determined division points (S707). As a reference power value, a method of determining an intermediate point between the divided points (906 in FIG. 9) is adopted. At this time, for the first division point, an intermediate point between the minimum output (0 W) and the first division point is determined as a reference RF power value 905. For the nth division point, an intermediate point between the nth division point and the maximum output is determined as a reference RF power value 907. The reference RF power value can be not only an intermediate point between the divided points, but also a maximum value, a minimum value, or an arbitrary point.

  Next, in the determined reference RF power values 905, 906, and 907, the sensor offset correction value is increased or decreased in the plus or minus direction, and the corrected residual reflected wave 908 is minimized in each reference RF power value. Such a sensor offset correction value is retrieved and set (S706, S707).

  This operation is repeated for n reference RF power values, and the corrected residual reflected wave 908 is within the range from the minimum output to the maximum output so that the value of the residual reflected wave 908 after correction falls within the threshold 804 of the residual reflected wave Adjust the offset correction value of the sensor. At this time, if the residual reflected wave does not fall below the threshold value at one division point setting, the residual reflected wave change curve 908 obtained by the first operation is compared with the threshold value and divided. Point resetting is repeated, and determination of the number of necessary division points and search and setting of the RF sensor offset correction value are repeated (S708).

  After the adjustment is completed, a power zone determination data array is created based on the data of the first to nth division points obtained here. Also, a correction value data array is created based on the RF sensor offset correction values for the first to nth reference RF power values (S709).

  Here, this work not only uses the residual reflected wave as a reference, but also uses the sensor offset itself of the RF sensor as a reference, and performs the same operation to create a power zone determination data array and a correction value data array. May be.

  As described above, in the present embodiment, a processing chamber for processing a material to be processed, a plasma generating high-frequency power source (magnetron) for generating plasma in the processing chamber, and supplying power to the processing chamber. A high-frequency power source for applying a high-frequency power to form a bias potential between the plasma and an electrode that supports the material to be processed installed in the processing chamber, and between the high-frequency power source and the antenna or electrode In the plasma processing apparatus having an automatic matching device for controlling the impedance of the transmission system to a constant value, an RF sensor installed in the impedance matching apparatus and monitoring the impedance, phase, etc. of a transmission line or a load such as plasma Offset deviation corresponding to the RF power level is applied to the monitor output. Cancel, the reference point as a reference of the detection value of the RF sensor (zero point) at all times to keep constant, it is possible to improve the matching accuracy.

  The correction amount of the offset value corresponding to the RF power stores a controller such as a CPU (Central Processing Unit) built in the automatic matching unit and a correction database (correction table) indicating the relationship between the RF power and the offset value. And storing the relationship between the magnitude of the RF power and the correction amount of the offset value in the correction database as a database that can be set in multiple stages or divided into multiple ranges. The database divides the range from the minimum power to the maximum power into an arbitrary number of points, and records the RF power corresponding to each range and the offset correction value.

  In this database, when the high-frequency power source outputs RF power, the controller of the automatic matching unit selects a correction value corresponding to the output value, and cancels the offset deviation by correcting the output of the RF sensor. The zero point of the RF sensor can always be kept constant, and matching accuracy can be improved.

  In this embodiment, since the relationship between the offset correction value of the RF sensor and the RF power is stored in the correction value database, correction according to the RF power being supplied from the high-frequency power source can be performed. That is, even when the magnitude of the RF power is continuously changed during power feeding, the offset correction value corresponding to the magnitude of the RF power before and after the change is stored in the correction database. The monitor output of the RF sensor can be corrected following the continuous power fluctuation without interrupting the power supply, and the monitor value of the RF sensor can be corrected appropriately.

  Furthermore, in such a correction mechanism, a correction correction database is prepared only corresponding to the power supply mode of the high frequency power supply, that is, the high frequency power supply can output a fundamental wave (sine wave) and a modulated wave. Assuming that the relationship between the offset value deviation amount and the RF power generated in each of these power supply modes is divided into multiple stages or multiple ranges and registered in the correction database, only the change in the RF power can be obtained. In addition, even when the power supply mode is changed, the zero point of the RF sensor can be kept constant and the monitor value of the RF sensor can be corrected appropriately. Even in this case, the division intervals of the respective correction databases do not have to be constant, and an arbitrary number of division points may be assigned.

  In addition, since the sensor offset value can be intentionally shifted by increasing or decreasing the correction amount stored in the correction database as necessary, by using this, the residual reflected wave at the completion of matching is used. The magnitude can be arbitrarily controlled, and the bias potential, that is, the value of Vp-p can be finely adjusted.

  As described above, stable sensing and matching control are realized without depending on the magnitude of the RF power, and continuous fluctuation of the RF power without interruption of the power feeding, as well as the fundamental wave and the modulated wave. Even for continuous fluctuations in the feeding mode such as the above, and changes that combine these, stable matching control is possible without interrupting the feeding of RF power, and Vp-p by controlling the residual reflected wave By enabling fine adjustment of the value, it is possible to realize a plasma processing apparatus capable of forming a stable bias potential and stabilizing the plasma.

It is a figure explaining a plasma etching apparatus. It is a figure explaining an impedance automatic matching apparatus. It is a figure explaining offset correction and matching control of the RF sensor in the automatic impedance matching device. It is a figure which shows an example of the database used by the process of sensor offset correction. It is a figure which shows an example of the database used by the process of sensor offset correction. It is a figure explaining the sensor characteristic of RF sensor. It is a figure explaining the process for creating the database used for offset correction. It is a figure which shows the impedance range assumed by database preparation work. It is a figure which shows an example of the criteria in determination of the division | segmentation point number and correction amount of the database for offset correction | amendment.

Explanation of symbols

101 Vacuum container 102 Material 103 Sample stage 104 Plasma
105 Antenna electrode
106 Air-core coil 107 Magnetron
108 Coaxial waveguide
109 Substrate electrode 110 High frequency power source
111 Gas supply device
112 Gas introduction plate 113 Vacuum exhaust device
114 Antenna electrode impedance automatic matching device
115 Isolator
116 Substrate electrode impedance automatic matching device
117 DC voltage source
118 Filter circuit
119 Master controller 201 RF sensor
202 A / D converter
203 Controller 204 CPU
205 storage device
206 I / O device 207, 208 Variable element
209, 210 Pulse motor
211 Motor controller
212 Communication path with high frequency power source

Claims (5)

A vacuum vessel that houses an antenna electrode to which high-frequency power for plasma generation is supplied and a substrate electrode to which high-frequency bias power is supplied is provided, and a material to be processed placed on the substrate electrode is generated by the generated plasma. In a plasma processing apparatus for performing plasma processing,
A high-frequency bias power source that supplies high-frequency bias power to the substrate electrode is inserted into a transmission path that connects the substrate electrode, and includes an automatic impedance matching unit that maintains a constant impedance of the transmission path as viewed from the high-frequency bias power source side,
The automatic impedance matching unit includes: a control device that adjusts an impedance element constituting the matching unit based on an output of an RF sensor that measures impedance or phase of the transmission line as viewed from the high-frequency bias power source; An offset correction unit that corrects the offset of the sensor output is provided.
The offset correction unit includes a storage device in which the magnitude of input power input to the matching unit is divided into multiple stages, and the offset correction value is set in advance for each of the multiple stages of input power. A plasma processing apparatus, wherein an offset of an output of the RF sensor is corrected according to a correction value set in the apparatus. The plasma processing apparatus according to claim 1,
The offset correction unit reads a correction value from the storage device according to the value of the input high-frequency bias power and performs offset correction on the output of the RF sensor without interrupting the supply of the high-frequency bias power A plasma processing apparatus that performs offset correction continuously. The plasma processing apparatus according to claim 1,
The high-frequency bias power source is continuously connected with any one of a power supply mode for supplying power of a waveform in which the fundamental wave is amplitude-modulated, a waveform in which the fundamental wave is frequency-modulated, or a waveform in which the fundamental wave is TM-modulated. Then, the plasma processing apparatus supplies the substrate electrode while switching. The plasma processing apparatus according to claim 1,
A plasma processing apparatus, wherein the magnitude of the peak-to-peak voltage applied to the substrate electrode can be arbitrarily controlled by adjusting the offset correction value. The plasma processing apparatus according to claim 1,
By adjusting the offset correction value, the magnitude of the residual reflected wave upon completion of matching can be arbitrarily controlled.

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