JP2009152345A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parallel flat plate type plasma processing apparatus which does not cause problems due to an abnormal discharge and can solve problems caused by reaction products sticking on an electrode, and to provide a plasma processing method. <P>SOLUTION: The plasma processing apparatus 1 comprises a processing chamber 2 in which a substrate G is stored, a lower electrode 3 and an upper electrode 20 provided in the processing chamber 2 opposite each other, a first high-frequency power source 14 which applies first high-frequency power of ≥10 MHz in frequency to the lower electrode 3, a second high-frequency power source 17 which applies second high-frequency power of ≥2 MHz and <10 MHz in frequency to the lower electrode 3, a third high-frequency power source 33 which applies high-frequency power of 400 kHz to 1.6 MHz in frequency to the second electrode 20, a gas supply mechanism 28 which supplies a processing gas for plasma generation into the processing chamber 2, and an exhausting mechanism 41 exhausting the chamber 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method for performing plasma such as dry etching on a substrate such as a glass substrate for manufacturing a flat panel display (FPD).

  For example, in an FPD manufacturing process or a semiconductor device manufacturing process, plasma processing such as dry etching is performed on a substrate such as a glass substrate or a semiconductor wafer. For such plasma processing, a parallel plate type plasma processing apparatus is frequently used.

  A parallel plate type plasma processing apparatus is provided with a mounting table for mounting a substrate in a chamber and a shower head for supplying a processing gas in a shower-like manner so that the mounting table functions as a lower electrode. Is made to function as an upper electrode, and a high frequency electric field is applied to at least one of them to form a high frequency electric field between them, and a plasma treatment is performed on the glass substrate by converting the processing gas into plasma by this high frequency electric field. .

  When such a parallel plate type plasma processing apparatus is applied as a plasma etching apparatus, a first high frequency power having a relatively high frequency is applied to a shower head which is an upper electrode, and a relative to a mounting table which is a lower electrode. In particular, an upper / lower application type that applies a second high-frequency power having a low frequency or a first high-frequency power having a relatively high frequency and a second high-frequency power having a relatively low frequency are applied to a mounting table that is a lower electrode. A lower two-frequency application type to be applied is also used, and a favorable etching process is performed by appropriately controlling plasma with such a configuration.

  By the way, in such a parallel plate type plasma processing apparatus including the upper lower application type and the lower two frequency application type, depending on discharge conditions, arc discharge occurs in the gas discharge hole of the shower head which is the upper electrode, and the shower is performed. The head (electrode plate held by the shower head) may be damaged to shorten the life or cause a device defect.

  As a technique for solving this problem, Patent Document 1 applies a second low-frequency power having a relatively low frequency to the upper electrode to increase the thickness of the plasma sheath of the upper electrode, so that the plasma flows into the gas discharge holes of the shower head. Technologies that prevent entry into the network have been proposed.

However, in this type of parallel plate type plasma processing apparatus, not only the problem due to such abnormal discharge but also device defects caused by reactive products adhering to the upper electrode occur, resulting in a decrease in yield. There is a problem and a problem that a maintenance cycle is shortened to remove such a reaction product and throughput is lowered.
JP 2006-286791 A

  The present invention has been made in view of such circumstances, and a parallel plate type plasma processing apparatus and a plasma that are free from problems caused by abnormal discharge and that can solve problems caused by reaction products adhering to electrodes. An object is to provide a processing method.

  In order to solve the above-described problem, according to a first aspect of the present invention, a processing chamber in which a substrate to be processed is accommodated, a first electrode and a second electrode provided opposite to each other in the processing chamber, and the first electrode First high frequency power applying means for applying a first high frequency power having a frequency of 10 MHz or more, and second high frequency power applying means for applying a second high frequency power having a frequency of 2 MHz or more and less than 10 MHz to the first electrode. A third high frequency power applying means for applying a high frequency power having a frequency of 400 kHz to 1.6 MHz to the second electrode, a gas supply mechanism for supplying a processing gas for generating plasma into the processing chamber, Provided is a plasma processing apparatus comprising an exhaust mechanism for exhausting a processing chamber.

  In the first aspect, the first electrode may be a support electrode that supports a substrate to be processed, and the second electrode may be a counter electrode provided to face the support electrode.

The third high-frequency power preferably has a frequency that does not interfere with the first and second high-frequency powers. Specifically, the frequency of the third high-frequency power is preferably such that the frequency of the first and second high-frequency powers does not become an integral multiple thereof. In addition, the third high frequency power is set to a power that can sufficiently remove the deposits attached to the first or second electrode and that the deposits do not adhere, and that the upper electrode is not easily consumed. It is preferable. The specific power is preferably in the range of 0.009 to 0.055 W / cm ² . Moreover, as a more preferable frequency range of the third high frequency power, a range of 600 kHz to 1.0 MHz can be exemplified.

Further, it is connected to the second electrode and has an optimum impedance for the frequency of the first high-frequency power, and a high impedance for the frequency of the second high-frequency power and the third frequency. The first impedance adjuster having the impedance adjusted as described above and the second electrode are connected to the second electrode, and the impedance is optimum with respect to the frequency of the second high-frequency power, and the frequency of the first high-frequency power and the frequency A second impedance adjuster that is impedance-adjusted so as to have a high impedance with respect to the third frequency can be provided. In this case, it is connected to the side wall of the processing chamber and has an optimum impedance for the frequency of the third high-frequency power, and a high impedance for the frequency of the first high-frequency power and the second frequency. It is also possible to further include a third impedance adjuster whose impedance is adjusted so that
An insulating substrate can be used as the substrate to be processed.

  In the second aspect of the present invention, a first electrode and a second electrode are provided opposite to each other in a processing chamber in which a substrate to be processed is accommodated, a high frequency electric field is formed therebetween, and a processing gas is generated by the high frequency electric field. A plasma processing method in which plasma treatment is performed on a target object by applying a plasma, and a first high frequency power having a frequency of 10 MHz or more and a second high frequency power having a frequency of 2 MHz or more and less than 10 MHz are applied to the first electrode. A plasma processing method comprising: generating plasma, applying high frequency power having a frequency of 400 kHz to 1.6 MHz to the second electrode, and cleaning the surface of the first electrode or the second electrode by sputtering. I will provide a.

  In the second aspect, as in the first aspect, the first electrode is a support electrode that supports the substrate to be processed, and the second electrode is a counter electrode provided to face the support electrode. can do.

As in the first aspect, it is preferable that the third high-frequency power has a frequency that does not interfere with the first and second high-frequency powers. Specifically, the frequency of the third high-frequency power is preferably such that the frequency of the first and second high-frequency powers does not become an integral multiple thereof. In addition, the third high frequency power is set to a power that can sufficiently remove the deposits attached to the first or second electrode and that the deposits do not adhere, and that the upper electrode is not easily consumed. It is preferable. The specific power is preferably in the range of 0.009 to 0.055 W / cm ² . Moreover, as a more preferable frequency range of the third high frequency power, a range of 600 kHz to 1.0 MHz can be exemplified.
An insulating substrate can be used as the substrate to be processed.

  According to the present invention, by applying the first and second high-frequency power to the first electrode, the plasma sheath can be spread to make it difficult for abnormal discharge to occur, and the third high-frequency power can be applied to the second electrode. The surface of the first or second electrode, typically the upper electrode, can be cleaned due to the sputtering effect.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a plasma processing apparatus according to an embodiment of the present invention. The plasma processing apparatus 1 is configured as a capacitively coupled parallel plate plasma etching apparatus that plasma etches a predetermined film of a glass substrate G for FPD. Here, as FPD, a liquid crystal display (LCD), an electroluminescence (Electro Luminescence; EL) display, a plasma display panel (PDP), etc. are illustrated.

  The plasma processing apparatus 1 has a processing chamber 2 formed into a rectangular tube shape made of aluminum, for example, whose surface is anodized (anodized). A mounting table 3 for mounting a glass substrate G as a substrate to be processed is provided at the bottom of the processing chamber 2.

  The mounting table 3 is supported on the bottom of the processing chamber 2 via an insulating member 4 and adsorbs the metallic convex base material 5 and the glass substrate G provided on the convex part 5a of the base material 5. The electrostatic chuck 6, the frame-shaped shield ring 7 made of insulating ceramics such as alumina, which is provided around the electrostatic chuck 6 and the convex portion 5 a of the base material 5, and the base material 5. Insulating ceramics, for example, a ring-shaped insulating ring 8 made of alumina. The electrostatic chuck 6 is configured such that an electrode 6b is embedded in a main body 6a made of a dielectric material such as ceramics. A feeding line 18 is connected to the electrode 6b, and a DC power source 19 is connected to the feeding line 18. When a DC voltage from the DC power source 19 is applied to the electrode 6b, electrostatic force such as Coulomb force is applied. The glass substrate G is adsorbed by the adsorbing force.

  Lifting pins 10 for loading and unloading the glass substrate G onto the bottom wall of the processing chamber 2, the insulating member 4, and the mounting table 3 are inserted so as to be able to move up and down. When the glass substrate G is transported, the elevating pins 10 are raised to the transport position above the mounting table 3, and are otherwise immersed in the mounting table 3.

  A power supply line 12 for supplying a first high frequency power is connected to the base material 5 of the mounting table 3, and a first matching unit 13 and a first high frequency power supply 14 are connected to the power supply line 12. Has been. A first high frequency power of 10 MHz or more, for example, 13.56 MHz is supplied from the first high frequency power supply 14 to the base material 5 of the mounting table 3. Further, a power supply line 15 for supplying the second high frequency power is connected to the base material 5, and a second matching unit 16 and a second high frequency power supply 17 are connected to the power supply line 15. Yes. From the second high frequency power supply 17, second high frequency power of 2 MHz or more and less than 10 MHz, for example, 3.2 MHz is supplied to the base material 5 of the mounting table 3. Therefore, the mounting table 3 functions as a lower electrode.

  Above the mounting table 3, a shower head 20 that functions as an upper electrode is provided in parallel with the mounting table 3. The shower head 20 is supported on the upper portion of the processing chamber 2 via an insulating member 29, has an internal space 21 inside, and has a plurality of gas discharge holes 22 for discharging a processing gas to the surface facing the mounting table 3. Is formed. The shower head 20 which is the upper electrode constitutes a pair of parallel plate electrodes together with the mounting table 3 which is the lower electrode.

A gas inlet 24 is provided on the upper surface of the shower head 20, and a processing gas supply pipe 25 is connected to the gas inlet 24, and the processing gas supply pipe 25 is connected to a processing gas supply source 28. Yes. Further, an opening / closing valve 26 and a mass flow controller 27 are interposed in the processing gas supply pipe 25. A processing gas for plasma etching is supplied from the processing gas supply source 28. As the processing gas, a gas usually used in this field, such as a halogen-based gas, an O ₂ gas, or an Ar gas, can be used.

  The shower head 20 as the upper electrode is connected to a power supply line 31 for supplying a third high-frequency power. The power supply line 31 is connected to a third matching unit 32 and a third high-frequency power supply 33. Is connected. A third high frequency power of 400 kHz or more and 1.6 MHz or less, for example, 750 kHz is supplied from the third high frequency power supply 33 to the shower head 20 that is the upper electrode. The frequency of the third high-frequency power is a frequency that does not interfere with the frequencies of the first and second high-frequency powers. That is, the frequency of the third high-frequency power is set not to be an integral fraction of the frequency of the first and second high-frequency powers. In other words, the frequency of the first and second high frequency powers is prevented from becoming an integral multiple of the frequency of the third high frequency power.

  A first impedance adjuster 34 for the first high-frequency power and a second impedance adjuster 35 for the second high-frequency power are connected to the upper outer side of the shower head 20 that is the upper electrode. .

  The first impedance adjuster 34 is configured by connecting a coil 36 and a variable capacitor 37 in series. The absolute value of the impedance with respect to the frequency of the first high-frequency power is low, and the absolute impedance with respect to the frequency of the other high-frequency power is low. The circuit constant is set so that the value becomes high, the first high-frequency power flows, and the second and third high-frequency powers hardly flow.

  The second impedance adjuster 35 is configured by connecting a coil 38 and a variable capacitor 39 in series. The absolute value of the impedance with respect to the frequency of the second high-frequency power is low, and the impedance with respect to the frequency of the other high-frequency power is low. Circuit constants are set so that the absolute value is high, the second high-frequency power flows, and the first and second high-frequency powers hardly flow.

  An exhaust pipe 40 is formed at the bottom of the processing chamber 2, and an exhaust device 41 is connected to the exhaust pipe 40. The exhaust device 41 includes a vacuum pump such as a turbo molecular pump, and is configured so that the inside of the processing chamber 2 can be evacuated to a predetermined reduced pressure atmosphere. A substrate loading / unloading port 42 is provided on the side wall of the processing chamber 2, and the substrate loading / unloading port 42 can be opened and closed by a gate valve 43. And the glass substrate G is carried in / out by a transfer device (not shown) with the gate valve 43 opened.

  Each component of the plasma processing apparatus 1 is controlled by the control unit 50. The control unit 50 includes a program storage unit that stores a control program for performing predetermined control, a controller that actually controls each component unit based on the control program, and a user interface that includes a keyboard, a display, and the like. is doing.

  Specifically, the control unit 50 includes the application timing of high frequency power from each high frequency power supply, control of these powers, control of gas supply and exhaust, drive control of gate valves, elevating pins, etc., electrostatic chuck Control such as voltage supply control to

Next, the processing operation in the plasma processing apparatus 1 configured as described above will be described.
First, the gate valve 43 is opened, and the glass substrate G is loaded into the processing chamber 2 through the substrate loading / unloading port 42 by a transfer arm (not shown) and placed on the electrostatic chuck 6 of the mounting table 3. . In this case, the elevating pins 10 are projected upward to be positioned at the support position, and the glass substrate G on the transfer arm is transferred onto the elevating pins 10. Thereafter, the elevating pins 10 are lowered to place the glass substrate G on the electrostatic chuck 6 of the mounting table 3.

  Thereafter, the gate valve 43 is closed, and the processing chamber 2 is evacuated to a predetermined vacuum level by the exhaust device 41. Then, the glass substrate G is electrostatically adsorbed by applying a voltage from the DC power source 19 to the electrode 6 b of the electrostatic chuck 6. Then, the valve 26 is opened, and the processing gas from the processing gas supply source 28 is adjusted in flow rate by the mass flow controller 27, while passing through the processing gas supply pipe 25 and the gas inlet 24, the internal space 21 of the shower head 20. Then, the gas is uniformly discharged to the substrate G through the discharge holes 22 and the inside of the processing chamber 2 is controlled to a predetermined pressure while adjusting the exhaust amount.

  In this state, the first high-frequency power of 10 MHz or more, for example, 13.56 MHz, is supplied from the first high-frequency power source 14 to the base material 5 of the mounting table 3 that is the lower electrode through the first matching unit 13. A second high frequency power of 2 MHz or more and less than 10 MHz, for example, 3.2 MHz, is supplied from the second high frequency power supply 17 via the second matching unit 16, and the mounting table 3 as the lower electrode and the shower head 20 as the upper electrode. A high-frequency electric field is generated between them to generate plasma of a processing gas, and a plasma etching process is performed on the glass substrate G by this plasma.

  Here, the frequency of the first high-frequency power is set to 10 MHz or more in a frequency band in which ions in the plasma cannot respond to the instantaneous electric field and a negative DC voltage (self-bias) is generated, and This is because the plasma density can be increased. The reason why the frequency of the second high-frequency power is set to 2 MHz or more and less than 10 MHz is to further accelerate the ions, promote the substrate surface reaction, and enhance the effect of anisotropic etching. This is because the ions inside follow the change in the electric field and cause ion collision (sputtering effect) instead of self-bias, which may cause damage to the substrate.

  Thus, by supplying the first high-frequency power and the second high-frequency power to the mounting table 3 that is the lower electrode and superimposing them, it is possible to appropriately control the plasma and perform a good etching process. If the etching is continued, the reaction product adheres to the surface of the shower head 20 which is the upper electrode, which may cause device defects and reduce the yield. Further, if the maintenance cycle is shortened so as not to cause such a device defect, the operation rate of the apparatus is lowered.

  From the viewpoint of preventing this, in the present embodiment, the shower head 20 that is the upper electrode is connected to the lower frequency of 400 kHz or more from the third high-frequency power source 33 via the third matching unit 32. A third high frequency power of 6 MHz, for example 750 KHz, is applied with an appropriate power. As a result, the plasma sheath of the upper electrode can be expanded to positively increase the sheath voltage, and the reaction product (attachment) adhering to the shower head 20 as the upper electrode can be dry cleaned by ion sputtering.

  The reason why the frequency of the third high-frequency power is in the range of 400 kHz to 1.6 MHz is that good sputtering force can be obtained in this range. An experiment confirming this will be described. Here, the lower electrode is regarded as the upper electrode, and an experiment for measuring the self-bias voltage (Vdc) of the lower electrode to which the high frequency power of each frequency is applied is performed, which is an index of the frequency and the sputtering force of the third high frequency power. The relationship with the self-bias voltage (Vdc) was obtained. The result is shown in FIG. FIG. 2 is a graph showing the relationship between the frequency of the high frequency power on the horizontal axis and the self-bias voltage (Vdc) on the vertical axis. From this graph, it can be seen that Vdc takes a maximum value at 800 kHz (0.8 MHz), and a high Vdc of 600 V or higher is obtained in the range of 400 kHz (0.4 MHz) to 1.6 MHz. A more preferable range is 600 kHz (0.6 MHz) to 1.0 MHz. A frequency that does not interfere with the frequencies of the first and second high-frequency powers is selected from such a frequency range.

  Next, an experiment that grasps the relationship between the power of the third high-frequency power and the sputtering force will be described. Here, a silicon wafer sample cut into a square of 30 mm × 30 mm is attached to the position of the upper electrode (220 cm × 250 cm) as shown in FIG. 3, and the frequency of 13.56 MHz as the first high-frequency power is applied to the lower electrode. Etch silicon wafer sample by applying 5 kW, high frequency power of 3.2 MHz as second high frequency power and high frequency power of 5 kW, applying high frequency power of 750 kHz as third high frequency power to the upper electrode while changing the power. I figured out the rate. The result is shown in FIG. FIG. 4 is a graph showing the relationship between the third high frequency power (750 kHz) on the horizontal axis and the average value of the etch rate of the silicon wafer on the vertical axis. As shown in this figure, it can be seen that applying the third high-frequency power increases the etch rate, that is, improves the sputtering effect of the deposit. It was confirmed that the etch rate increased as the power of the third high-frequency power increased.

For this reason, it is necessary to supply the third high-frequency power by setting the power so that the reaction product (adhesion) can be sufficiently removed and the reaction product does not adhere. However, since the upper electrode is consumed if the power of the third high-frequency power is too large, it is necessary to set the power to an appropriate level that does not cause this. A preferable range of the power of the third high-frequency power is about 0.009 to 0.055 W / cm ² .

  As a method of cleaning the shower head 20 that is the upper electrode by the third high-frequency power, when the glass substrate G is subjected to the etching process, the first and second high-frequency power is applied with a slight delay after the application. 3 is applied to remove the reaction product adhering to the shower head 20 as the upper electrode in real time, so that the reaction product does not appear to adhere. Alternatively, after a predetermined number of plasma treatments of the glass substrate G are performed by applying the first and second high-frequency power, a dummy substrate is placed at the turn of the lot, for example, or nothing is placed on the mounting table. In addition to the first and second high frequency powers, the third high frequency power may be supplied to clean the shower head 20 as the upper electrode. The first and second high frequency powers and the third high frequency power may be applied simultaneously. As another method, only the first high-frequency power and the third high-frequency power can be supplied when only cleaning is performed.

Next, impedance adjustment will be described.
The glass substrate targeted by the present embodiment is steadily increasing in size, and one side exceeds 2 m. When performing plasma treatment on such a large glass substrate, the apparatus is also large. Therefore, it is difficult to form the plasma uniformly, and the plasma tends to be biased. Therefore, from the viewpoint of preventing such plasma bias, the first impedance adjuster 34 for the first high-frequency power is provided outside the upper portion of the shower head 20 as the upper electrode, as schematically shown in FIG. A second impedance adjuster 35 for the second high-frequency power, the first impedance adjuster 34 optimizes the impedance for the first high-frequency power so that only the first high-frequency power flows, The second impedance adjuster 35 optimizes the impedance with respect to the second high-frequency power so that only the second high-frequency power flows, and the first high-frequency power and the second high-frequency power are sent to the shower head 20 as the upper electrode. Therefore, the high frequency power is not biased. That is, the first impedance adjuster 34 and the second impedance adjuster 35 have a filter function in addition to the impedance adjustment function.

  Although such an impedance adjuster has been used conventionally, in the present embodiment, the first and second impedance adjusters 34 and 35 are used to supply the third high-frequency power to the shower head 20 that is the upper electrode. In addition to the above functions, the circuit constants of the first and second impedance adjusters 34 and 35 are set so that the third high-frequency power does not flow to the ground side through the first and second impedance adjusters 34 and 35. There is a need to. That is, as shown in FIG. 5, the first impedance adjuster 34 optimizes the impedance for the first high-frequency power, and sets the circuit constant so that the absolute value of the impedance for the second and third high-frequency power becomes high. The second impedance adjuster 35 optimizes the impedance with respect to the second high-frequency power, and the absolute value of the impedance with respect to the first and third high-frequency power is set so that only the first high-frequency power flows. The circuit constant is set to be high so that only the second high frequency power flows. Since the third high-frequency power does not flow to the ground side through the first and second impedance adjusters 34 and 35 as described above, it flows to the side wall portion side of the processing chamber 2 as shown in FIG. In this case, as shown in FIG. 6, a third impedance adjuster 45 is provided on the side wall of the processing chamber 2 to optimize the impedance for the third high-frequency power, and the absolute impedance for the first and second high-frequency powers. It is also possible to set the circuit constant so as to increase the value so that only the second high frequency power flows, and to allow the third high frequency power to actively flow through the side wall.

  As described above, by adjusting the impedance by the first and second impedance adjusters 34 and 35, the first and second high frequency powers are promptly transferred from the mounting table 3 as the lower electrode to the shower head 20 as the upper electrode. Since the third high-frequency power flows to the side wall of the processing chamber 2 as it flows, the third high-frequency power does not adversely affect the plasma generated by the first and second high-frequency power.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above embodiment, the first and second high-frequency powers are supplied to the lower electrode, and the third high-frequency power is supplied to the upper electrode. However, the first and third high-frequency powers are supplied to the upper electrode, The second high frequency power may be supplied to the lower electrode. In the above embodiment, the case where the present invention is applied to the plasma processing of the glass substrate for FPD which is an insulator is shown. However, the present invention is not limited to this and can be applied to various other substrates. .

Sectional drawing which shows the plasma processing apparatus which concerns on one Embodiment of this invention. The figure which shows the relationship between the frequency of 3rd high frequency electric power, and Vdc. The figure which shows the sample position of the upper electrode in the experiment which grasped | ascertained the relationship between the power of 3rd high frequency electric power, and sputtering power. The figure which shows the relationship between the power of 3rd high frequency electric power (750 kHz), and the average value of an etching rate. The schematic diagram for demonstrating an impedance regulator. The figure which shows the state which provided the impedance regulator for 3rd high frequency electric power.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Plas processing apparatus 2; Processing chamber 3; Mounting stand 5; Base material 6; Electrostatic chuck 14; First high frequency power source 17; Second high frequency power source 20; Shower head 28; Processing gas supply source 33; High frequency power supply 34; first impedance adjuster 35; second impedance adjuster 45; third impedance adjuster 50; control unit G; glass substrate

Claims (18)

A processing chamber in which a substrate to be processed is accommodated;
A first electrode and a second electrode provided opposite to each other in the processing chamber;
First high-frequency power application means for applying a first high-frequency power having a frequency of 10 MHz or more to the first electrode;
Second high frequency power application means for applying a second high frequency power having a frequency of 2 MHz or more and less than 10 MHz to the first electrode;
Third high frequency power applying means for applying high frequency power having a frequency of 400 kHz or more and 1.6 MHz or less to the second electrode;
A gas supply mechanism for supplying a processing gas for generating plasma into the processing chamber;
A plasma processing apparatus comprising an exhaust mechanism for exhausting the processing chamber.   The plasma processing apparatus according to claim 1, wherein the first electrode is a support electrode that supports a substrate to be processed, and the second electrode is a counter electrode that is provided to face the support electrode.   The plasma processing apparatus according to claim 1, wherein the third high-frequency power has a frequency that does not interfere with the first and second high-frequency powers.   4. The plasma processing apparatus according to claim 3, wherein the frequency of the third high-frequency power is a frequency such that the frequencies of the first and second high-frequency powers do not become integer multiples thereof.   The third high-frequency power is set to a power that can sufficiently remove the deposit attached to the first or second electrode and does not adhere to the deposit, and does not easily deplete the upper electrode. The plasma processing apparatus according to any one of claims 1 to 4, wherein the plasma processing apparatus is characterized. The plasma processing apparatus according to claim 5, wherein the power of the third high-frequency power is in the range of 0.009 to 0.055 W / cm ² .   The plasma processing apparatus according to any one of claims 1 to 6, wherein the frequency of the third high-frequency power is in a range of 600 kHz to 1.0 MHz. It is connected to the second electrode and has an optimum impedance for the frequency of the first high-frequency power, and a high impedance for the frequency of the second high-frequency power and the third frequency. A first impedance adjuster that is impedance adjusted;
It is connected to the second electrode and has an optimum impedance for the frequency of the second high-frequency power, and a high impedance for the frequency of the first high-frequency power and the third frequency. The plasma processing apparatus according to any one of claims 1 to 7, further comprising a second impedance adjuster whose impedance is adjusted.   It is connected to the side wall of the processing chamber and has an optimum impedance for the frequency of the third high-frequency power, and a high impedance for the frequency of the first high-frequency power and the second frequency. The plasma processing apparatus according to claim 8, further comprising a third impedance adjuster whose impedance is adjusted.   The plasma processing apparatus according to any one of claims 1 to 9, wherein an insulating substrate is used as a substrate to be processed. A first electrode and a second electrode are provided opposite to each other in a processing chamber in which a substrate to be processed is accommodated, and a high frequency electric field is formed between them. A plasma processing method for applying
Applying a first high-frequency power having a frequency of 10 MHz or more and a second high-frequency power having a frequency of 2 MHz or more and less than 10 MHz to the first electrode to generate plasma,
A plasma processing method, comprising applying a third high frequency power having a frequency of 400 kHz to 1.6 MHz to the second electrode to sputter and clean the surface of the first electrode or the second electrode.   The plasma processing according to claim 11, wherein the first electrode is a support electrode that supports a substrate to be processed, and the second electrode is a counter electrode provided to face the support electrode. Method.   The plasma processing method according to claim 11 or 12, wherein the third high-frequency power has a frequency that does not interfere with the first and second high-frequency powers.   14. The plasma processing method according to claim 13, wherein the frequency of the third high-frequency power is a frequency such that the frequencies of the first and second high-frequency powers are not integral multiples thereof.   The third high-frequency power is set to a power that can sufficiently remove deposits adhering to the first electrode or the second electrode so that the deposits do not adhere, and that the upper electrode is not easily consumed. The plasma processing method according to any one of claims 11 to 14, wherein: The plasma processing method according to claim 15, wherein the power of the third high-frequency power is in the range of 0.009 to 0.055 W / cm ² .   The plasma processing method according to any one of claims 11 to 16, wherein a frequency of the third high-frequency power is in a range of 600 kHz to 1.0 MHz. The plasma processing method according to claim 11, wherein an insulating substrate is used as the substrate to be processed.

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