JPH09266095A - Plasma treatment device and its treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment device in which adhesion of particle to a sample or metal contamination is minimized by changing the form of a counter electrode near the lower surface of a microwave inlet window. SOLUTION: This plasma treatment device has a means for supplying a microwave (35: microwave transmitter, 34: waveguide, 32: dielectric layer); a reactor vessel 11 having a microwave inlet window 14 and a sample stage 15 opposed to the microwave inlet window 14; a high frequency power source 28 for applying a high frequency to the sample stage 15; and an electrically grounded counter electrode 21 opposed to the sample stage 15. The counter electrode 21 is provided on the peripheral part of the microwave inlet window 14 on the inside of the reactor vessel 11. The form of the counter electrode 21 is preferably symmetric, seen from a sample S, so that the sample S is subjected to an uniform plasma treatment. Further, it is preferably annular from the viewpoint of device structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method used for etching, ashing, CVD and the like in manufacturing large scale integrated circuits (LSI) and liquid crystal displays (LCD).

[0002]

2. Description of the Related Art Plasma of a reactive gas is widely used in the manufacturing process of LSI and LCD.
Especially dry etching technology using plasma
It has become an indispensable basic technology in the manufacturing process of LCD and the like.

On the other hand, with the recent increase in the size of substrates used for manufacturing LSIs and LCDs, it is required to generate uniform plasma in a large area. Further, in the dry etching technique and the embedding technique in thin film formation, it is required to independently control the generation of plasma and the energy of ions in the plasma.

The applicant of the present invention has already proposed a plasma processing apparatus capable of generating uniform plasma over a large area and controlling the energy of ions (Japanese Patent Laid-Open No. Hei.
No. 1447773). In this device, the ceiling of the reaction vessel is hermetically sealed with a dielectric plate (hereinafter, referred to as a microwave introduction window) capable of transmitting microwaves, and the microwave propagates above the microwave introduction window. A dielectric layer is provided and a high frequency is applied to the sample table.

In this device, since the microwaves are propagated in a plane to the dielectric layer, it is possible to easily generate a uniform plasma over a wide area by increasing the areas of the dielectric layer and the microwave introduction window. it can. Further, when a high frequency is applied to the sample stage, an electric circuit is formed between the sample stage-plasma-grounding portion via plasma, and a bias voltage can be generated on the sample surface. The bias voltage controls the acceleration of ions in the plasma (energy of ions). That is, the plasma is generated mainly by microwaves, and the energy of the ions in the plasma is controlled mainly by the high frequency, so that the generation of the plasma and the energy of the ions in the plasma can be controlled independently.

However, this device cannot generate a stable bias voltage on the surface of the sample depending on the plasma generation conditions, and it is sometimes difficult to control the energy of the ions. For example, in the etching of an oxide film, depending on the etching conditions, not only the oxide film cannot be etched with good reproducibility, but there is also a problem that the etching does not proceed and a thin film is deposited on the sample.

Therefore, the present applicant has further proposed a device capable of stably controlling the energy of this ion (Japanese Patent Laid-Open No. 6-104098).

FIG. 12 is a schematic vertical sectional view of a plasma processing apparatus capable of stably controlling the energy of the ions. In this device, a counter electrode 41 electrically grounded on the reaction chamber 12 side of the microwave introduction window 14 is provided.
Is provided.

FIG. 13 is a schematic plan view of the counter electrode 41. The counter electrode 41 is made of a metal plate such as aluminum (Al) and has a microwave supply hole 41 a for introducing a microwave into the reaction chamber 12.

In this apparatus, the grounded counter electrode 41 is provided so as to face the sample stage 15 and in the vicinity of the microwave introduction window in which plasma is mainly generated. Therefore, it is possible to stabilize the plasma potential when a high frequency is applied to the sample table 15 and generate a stable bias voltage on the surface of the sample S. As a result, it becomes possible to control the energy of the ions in the plasma, and it is possible to irradiate the surface of the sample S with the ions having the appropriate energy.

[0011]

However, in the apparatus having the above structure, since the counter electrode is directly above the sample, the material of the counter electrode or the deposit generated in the plasma and attached to the counter electrode is sputtered by the plasma. Then, the sample S adheres to the sample S and causes a problem of particles and metal contamination.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a plasma processing apparatus and a plasma processing method in which particles adhere to a sample and metal contamination is small. Further, another object of the present invention is to provide a plasma processing apparatus and a plasma processing method capable of performing more uniform processing over a wide area.

[0013]

As described above, in order to control the energy of the ions in the plasma to irradiate the sample, a high frequency is applied to the sample table to generate a bias voltage on the surface of the sample. When a high frequency is applied to the sample table,
An electric circuit is formed through the plasma, but the plasma potential is related to the bias voltage generated on the surface of the sample, and this plasma potential is related to the grounded metal (which plays the role of the counter electrode). It changes greatly depending on whether they are in contact with each other.

Therefore, in the apparatus for generating the high density plasma just below the microwave introduction window as described above,
In order to stably control the energy of ions, it is necessary to provide this counter electrode near the place where the high-density plasma is generated, that is, near the lower surface of the microwave introduction window.

The inventors of the present invention performed etching of the sample by changing the shape of the counter electrode in the vicinity of the lower surface of the microwave introduction window in order to study the counter electrode with less particles and metal contamination. As a result, it is possible to reduce particles and metal contamination by using only the peripheral electrode that does not have a portion (directly above the sample) that directly opposes the sample stage. Moreover, stable plasma processing is possible even with an electrode only on the peripheral portion. It has been found that can be applied to the sample. The present invention has been completed based on the above findings, and its gist is (1) to (4) below.

(1) A means for supplying microwaves, a reaction vessel having a microwave introduction window and a sample stand facing the microwave introduction window, means for applying a high frequency to the sample stand, and a sample stand facing the sample stand. And a counter electrode that is electrically grounded, wherein the counter electrode is provided inside the reaction vessel and at the peripheral edge of the microwave introduction window.

(2) In the plasma processing apparatus of (1), the plasma processing is provided with a microwave adjusting plate made of metal and having a microwave supply hole in the vicinity of the outer surface of the reaction vessel of the microwave introducing window. apparatus.

(3) The plasma processing apparatus according to (1) or (2), which is provided with plasma focusing means made of an annular dielectric material in the vicinity of the inner surface of the reaction container of the microwave introduction window. apparatus.

(4) A plasma processing method in which the sample is subjected to plasma processing by using the plasma processing apparatus according to the above (1) to (3).

In the device of the present invention, the counter electrode is provided at the peripheral portion of the microwave introduction window so as to avoid the position directly above the sample. There is no metal that is a source of particles or a source of contamination directly above the sample. Therefore, it is possible to perform plasma processing with a stable bias voltage while suppressing the problems of particles adhering to the sample and metal contamination. The peripheral portion in the present invention means a portion directly above the sample as a central portion and an outer portion of the central portion.

Further, by providing a microwave adjusting plate which is a metal plate having a microwave supply hole in the vicinity of the outer surface of the reaction vessel of the microwave introducing window, the introduction of the microwave into the reaction chamber is adjusted. can do. Since the microwave adjusting plate is provided outside the reaction container, it is possible to adjust the electric field distribution of the microwave and perform more uniform plasma treatment on the sample while suppressing particles and metal contamination of the sample.

Further, by providing the plasma focusing means composed of the annular dielectric, the electric field strength of the microwave inside the annular dielectric can be strengthened and the plasma can be focused on the central portion. By utilizing this, the plasma density distribution can be adjusted to enable more uniform plasma processing.

In etching, for example, when the plasma density distribution is uniform, there is no object to be etched outside the sample, so that the peripheral portion of the sample is different from the central portion in the etching species containing ions irradiated per unit area. On the contrary, the amount tends to increase. Also, on the outside completely away from the sample, the etching species do not contribute to the etching,
It may disappear or be evacuated on the wall of the reaction vessel or around the sample table.

Therefore, by providing this annular dielectric close to the microwave introduction window, the plasma is focused on the central portion, and the amount of etching species irradiated to the peripheral portion of the sample and further outside thereof is reduced. This enables a more uniform and high-speed etching process.

The term "annular" as used herein is not limited to the one obtained by cutting out the center of a circular plate, but may be the one obtained by cutting out an elliptical plate or a rectangular plate. Further, it does not necessarily mean a continuous annular shape, and may be a shape in which a part of the annular shape is missing. That is, the shape may be designed according to the state of the plasma-treated sample.

By subjecting the sample to the plasma treatment using the above-described apparatus, it is possible to reduce the adhesion of particles to the sample and the metal contamination, and to treat the sample more uniformly. Therefore, when this plasma processing method is used, for example, in the manufacturing process of a semiconductor device, the yield of manufactured semiconductor devices can be improved.

Particularly, in the step of etching the silicon oxide film, it is important to control the ion energy.
More preferably, the sample is subjected to plasma treatment using the apparatus described above.

The above-mentioned grounded counter electrode, microwave adjusting plate, and plasma focusing means can obtain particularly high effects when applied to a plasma processing apparatus using a dielectric layer. The plasma processing device using this dielectric layer generates a large-area high-density plasma directly under the microwave introduction window where the microwave electric field is strong, so control of this part is more important than other devices. is there.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION A plasma processing apparatus and a plasma processing method according to the present invention will be specifically described.

(First Embodiment) FIG. 1 is a schematic vertical sectional view of a first embodiment of the plasma processing apparatus of the present invention. 1 in the figure
Reference numeral 1 denotes a hollow rectangular parallelepiped reaction vessel, which is formed of a metal such as aluminum or stainless steel. Reaction vessel 11
A reaction chamber 12 is provided inside. Reaction vessel 1
In the upper part of 1, a microwave introduction port 13 is opened,
The microwave introduction port 13 is hermetically sealed by a microwave introduction window 14 between the microwave introduction port 13 and the upper wall of the reaction vessel 11 via an O-ring 20. The microwave introduction window 14 is
It is formed of a dielectric material such as quartz glass (SiO ₂ ), alumina (Al ₂ O ₃ ), which has heat resistance and microwave transparency and has a small dielectric loss.

A sample stage 15 is arranged in the reaction chamber 12 at a position facing the microwave introduction window 14, and the sample S is placed on the sample stage 15. The sample table 15 is provided with an adsorption mechanism (not shown) such as an electrostatic chuck for holding the sample S and a circulation mechanism (not shown) for circulating a medium for holding the sample S at a constant temperature. . Furthermore, the sample table 15
A high frequency power supply 28 is connected to the. High frequency power supply 2
The frequencies of 8 are 400 kHz, 2 MHz, 13.
56 MHz or the like is used. The sample base 15 is fixed on a base 16, insulated from the reaction vessel 11 by an insulating member 18, and the periphery of the sample base 15 is surrounded by the plasma shield member 1.
Covered with 7. The sample table 15 has a structure in which alumina is sprayed on the surface of an aluminum electrode in order to have an electrostatic chuck function. Alumina is used as the insulating member 18 and the plasma shield member 17.

The reaction container 11 is provided with a gas introduction hole 25 for introducing a gas into the reaction chamber 12 and an exhaust port 26 connected to an exhaust device (not shown). The peripheral wall of the reaction vessel 11 can be heated to a predetermined temperature by a heater (not shown).

A dielectric layer 32 having an upper portion covered with a metal plate 33 such as aluminum is disposed above the reaction vessel 11. A microwave oscillator 35 is connected to the dielectric layer 32 via a waveguide 34. In addition, this dielectric layer 3
Reference numeral 2 is made of a material having a small dielectric loss, for example, fluororesin, polyethylene, polystyrene or the like. As the frequency of the microwave, for example, 2.45 GHz is used.

In this embodiment, in addition to the above configuration, in order to stabilize the bias voltage generated on the surface of the sample S,
An annular counter electrode 21 is provided on the lower surface of the microwave introduction window 14 at the peripheral portion thereof. The counter electrode 21 is electrically grounded via the reaction container 11 and serves as a ground electrode for the sample stage 15 to which a high frequency is applied.

FIG. 2 is an enlarged view of a portion A of the counter electrode portion of the apparatus shown in FIG. On the outer peripheral portion of the counter electrode 21, a counter electrode outer edge insulating plate 22 made of alumina or the like is provided, and the counter electrode 21 and the side wall of the reaction vessel 11 are divided.

FIG. 3 (a) is a schematic vertical sectional view of an annular electrode which is an example of this counter electrode, and FIG. 3 (b) is a bottom view of this annular electrode. The counter electrode 21 is made of silicon (Si), aluminum, or the like.

The shape of the counter electrode 21 is preferably symmetrical with respect to the sample in order to perform uniform plasma treatment on the sample. Further, from the viewpoint of the device configuration, it is preferable to make it annular, but it goes without saying that it is not limited to this.

When the surface of the sample S is etched by using the plasma processing apparatus having the above-mentioned structure,
It will be described with reference to FIG.

The reaction chamber 12 is exhausted from the exhaust port 26, and then gas is supplied to the reaction chamber 12 from the gas introduction hole 25.

A microwave is oscillated from the microwave oscillator 35 and introduced into the dielectric layer 32 through the waveguide 34. A surface wave electric field is formed in the hollow layer 31, the electric field is transmitted through the microwave introduction window 14, and the reaction chamber 12
To generate plasma.

High frequency power source 2 almost simultaneously with plasma generation
A high frequency is applied to the sample stage 15 using 8 to generate a bias voltage on the surface of the sample S. While controlling the energy of ions in the plasma by this bias voltage, the sample S
The sample S is etched by irradiating the surface of the sample with ions.

At this time, by providing the grounded counter electrode 21 having a shape that avoids directly above the sample S, there is no problem of particles adhering to the sample S or metal contamination, and the sample S is free from problems.
The bias voltage generated on the surface is stabilized and stable etching becomes possible.

When this plasma processing apparatus is applied to the semiconductor element manufacturing process, adhesion of particles to the sample and metal contamination can be reduced, and the sample can be uniformly processed, so that the yield of the manufactured semiconductor element is improved. You can

Incidentally, for example, a silicon oxide film (SiO ₂ )
This plasma processing apparatus is suitable for a process in which the control of ions is particularly important, such as the etching process of 1.

(Second Embodiment) FIG. 4 is a schematic vertical sectional view of a second embodiment of the plasma processing apparatus of the present invention. In the apparatus shown in FIG. 1, a microwave adjusting plate 23 is further provided on the microwave introducing window 14.

FIG. 5 is a plan view of this microwave adjusting plate. The microwave adjusting plate 23 is provided at the center of a metal plate such as aluminum, that is, at the portion above the sample S.
It is manufactured by providing a plurality of holes 23a. By the pattern of the holes 23a, the electric field distribution of the microwave introduced into the reaction chamber 12 is adjusted to enable more uniform plasma processing.

If only the non-uniformity of the plasma processing in the central portion and the peripheral portion of the sample is a problem, a metal plate having only one hole in the central portion may be used.

(Third Embodiment) FIG. 6 is a schematic vertical sectional view of a third embodiment of the plasma processing apparatus of the present invention. The apparatus shown in FIG. 4 is further provided with a plasma focusing means 24 made of an annular dielectric inside the counter electrode 21.

FIG. 7 is a schematic plan view of an example of the plasma focusing means made of this annular dielectric. This example is a perfect concentric ring. Quartz, alumina, or the like can be used as the material of the annular dielectric. Needless to say, the shape of the dielectric may be appropriately designed according to the result of plasma treatment of the sample.
Further, the plasma focusing means made of this annular dielectric is
It may be integrally formed with the microwave introduction window, or may be a member separate from the microwave introduction window for easy replacement in consideration of maintainability.

The plasma focusing means composed of this annular dielectric is useful for etching a silicon oxide film where the supply of etching species is particularly problematic. The reason for this is that the generation of plasma in unnecessary parts that are not irradiated on the sample is suppressed, and the amount of etching species supplied to the sample is increased by focusing the plasma on the central part of the sample, and the central part of the sample and the peripheral edge of the sample. This is because it is possible to speed up the etching and improve the uniformity by adjusting the amount of etching species of the portion.

[0051]

An embodiment of the present invention will be described. The microwave frequency used in the following examples is 2.45G.
The frequency of Hz and high frequency is 400 kHz.

(First Embodiment) The apparatus of this embodiment is the plasma processing apparatus shown in FIG. Using the apparatus of this example, 25 6-inch silicon wafers each having a silicon oxide film of 1 μm were continuously etched, and the number of particles of 0.2 μm or more on the wafer was measured. The etching conditions are as follows. CHF ₃ : 20 sccm, pressure: 30 mTorr, microwave power: 1300 W, high frequency power: 1000 W, sample stage temperature: 0 ° C. As a comparative example, the same measurement was performed for the conventional plasma processing apparatus shown in FIG.

As a result, in the conventional example, the number of particles on the wafer was several hundred, whereas in the example of the present invention, the number of particles on the wafer could be reduced to less than 50.

Particles on the wafer in the present invention were analyzed by EDX (energy dispersive X-ray analyzer) and found to be aluminum (Al) and fluorine (F).
Was not detected at the same time, and it was confirmed that particles and contamination from the counter electrode portion were reduced.

(Second Embodiment) The apparatus of this embodiment is shown in FIG.
It is a plasma processing apparatus provided with the microwave adjusting plate shown in FIG. Using this apparatus, the effect of plasma homogenization by the microwave adjusting plate was evaluated.

The uniformity of the plasma was evaluated by the uniformity of the film formation rate distribution of the polymer of fluorocarbon produced on the 6-inch silicon wafer when the CHF ₃ gas was decomposed by the plasma. The film forming conditions are as follows. CHF
₃ : 20 sccm, pressure: 30 mTorr, microwave power: 1
At 300 W, sample table temperature: 0 ° C., no high frequency power was applied to the sample table. In addition, as a comparative example, the same measurement was performed when the microwave adjusting plate was not used.

FIGS. 8 (a) and 8 (b) are views showing the opening pattern of the microwave adjusting plate used in the apparatus of this embodiment. FIG. 8 (a) limits the microwave transmission region to the central rectangular region, and FIG. 8 (b) further adjusts the microwave electric field distribution.

FIG. 9 is a diagram showing the film-forming rate distribution of the fluorocarbon polymer on the wafer surface. FIG. 9 (a)
When the microwave adjusting plate having the opening pattern shown in FIG. 8A is used, FIG. 9B is obtained when the microwave adjusting plate having the opening pattern shown in FIG. 8B is used. [Fig. 4] is a diagram showing a film forming rate distribution when a microwave adjusting plate is not used.
The unit is nm / min.

When the microwave adjusting plate was not used, the film formation rate was high on the microwave introducing side and the reflecting side. On the other hand, a uniform film formation rate distribution was obtained by providing the microwave adjusting plate. That is, by installing the microwave adjusting plate, plasma with a uniform density distribution could be generated.

(Third Embodiment) The apparatus of this embodiment is shown in FIG.
The plasma processing apparatus shown in FIG. Using this device,
The effect of homogenizing the plasma treatment by the plasma focusing means was evaluated. The plasma focusing means of this embodiment is the annular quartz shown in FIG. Further, the microwave adjusting plate having the opening pattern shown in FIG. 9A was used.

The effect of making the plasma treatment uniform was evaluated by the uniformity of the etching rate of the BPSG film on the 6-inch silicon wafer. The etching conditions are as follows. C
HF ₃ : 20 sccm, pressure: 30 mTorr, microwave power: 1300 W, high frequency power: 600 W, sample stage temperature:
0 ° C. In addition, as a comparative example, the same measurement was performed when the plasma focusing means was not used.

FIG. 10 is a diagram showing the distribution of the etching rate within the wafer surface. FIG. 10 (a) shows the results of the present invention, and FIG. 10 (b) shows the results of the comparative example. The unit is n
m / min. In FIG. 10B of the comparative example, the etching rate at the microwave reflection end and the peripheral portion is high and the distribution is non-uniform. On the other hand, FIG.
In (a), the etching rate could be improved and the distribution could be made uniform.

(Fourth Embodiment) The influence of the microwave adjusting plate and the plasma focusing means on the plasma density was measured. The plasma generation conditions are as follows. C
HF ₃ : 20 sccm, microwave power: 1300 W. The pressure was varied between 10 mTorr and 80 mTorr. High frequency power was not applied. A Langmuir probe was used to measure the plasma density. The measurement position was the center position of the sample table, and the position was 40 mm from the microwave introduction window.

FIG. 11 is a graph showing the measurement results of the plasma density. ◯ is the measurement result of the device used in the first embodiment, and Δ is the measurement result of the device used in the second embodiment using the microwave adjusting plate having the opening pattern of FIG. 8A. , □ are the measurement results of the device used in the third embodiment.

The plasma density could be increased by providing the microwave adjusting plate (Δ). This is because the electric field density of microwaves is increased by reducing the area of the microwave supply region.

Further, it was confirmed that the plasma density can be remarkably increased by providing the plasma focusing means made of quartz in the ring shape (□).

[0067]

As described in detail above, according to the plasma processing apparatus of the present invention, it is possible to generate a uniform plasma in a large area, control the ion energy, and reduce the adhesion of particles to the sample and the metal contamination. be able to. Furthermore, more uniform plasma processing can be enabled.

Further, when the plasma processing method of the present invention is applied to the manufacturing process of a semiconductor device, adhesion of particles to a sample and metal contamination can be reduced, and the sample can be uniformly processed. Can be improved.

[Brief description of drawings]

FIG. 1 is a schematic longitudinal sectional view of a first embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is an enlarged view of a portion A of the counter electrode 21 portion in FIG.

FIG. 3 (a) is a schematic vertical cross-sectional view of an annular electrode that is an example of this counter electrode, and FIG. 3 (b) is a schematic bottom view of this annular electrode.

FIG. 4 is a schematic vertical sectional view of a second embodiment of the plasma processing apparatus of the present invention.

FIG. 5 is a schematic plan view of a microwave adjusting plate of the present invention.

FIG. 6 is a schematic vertical sectional view of a third embodiment of the plasma processing apparatus of the present invention.

FIG. 7 is a schematic plan view of an example of plasma focusing means of the present invention.

FIG. 8 is a diagram showing an opening pattern of the microwave adjusting plate of the present invention. FIG. 8 (a) limits the microwave supply area to the central rectangular area, and FIG. 8 (b) further adjusts the microwave distribution.

FIG. 9 is a diagram showing a film formation rate distribution of a fluorocarbon polymer on a wafer surface. FIG. 9A shows a case where the microwave adjusting plate having the opening pattern shown in FIG.
FIG. 9B is a diagram showing a film forming rate distribution when the microwave adjusting plate having the opening pattern of FIG. 8B is used and FIG. 9C is a film forming speed distribution when the microwave adjusting plate is not used.

10A and 10B are diagrams showing an etching rate distribution in a wafer surface, FIG. 10A is a diagram showing a result of an example of the present invention, and FIG. 10B is a diagram showing a result of a comparative example. .

FIG. 11 is a graph showing measurement results of plasma density. ◯ is the measurement result of the device used in the first embodiment,
△ is the measurement result of the device used in the second embodiment, □
Is the measurement result of the apparatus used in the third embodiment.

FIG. 12 is a schematic vertical sectional view of a conventional plasma processing apparatus.

13 is a plan view of a conventional grounded counter electrode 41. FIG.

[Explanation of symbols]

 Reference Signs List 11 reaction vessel 12 reaction chamber 13 microwave introduction port 14 microwave introduction window 15 sample table 16 base 17 plasma shield member 18 insulating member 20 O-ring 21 counter electrode 22 counter electrode outer edge insulating plate 23 microwave adjusting plate 23a hole 24 plasma focusing Means 25 Gas introduction hole 26 Exhaust port 31 Hollow part 32 Dielectric layer 33 Metal plate 34 Waveguide 35 Microwave oscillator 41 Counter electrode 41a Hole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H01L 21/205 H01L 21/205 21/285 21/285 C 21/3065 21/31 C 21/31 21/302 B (72) Inventor Tomomi Murakami 4-533 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd. (72) Inventor Naohiko Takeda 4-53 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture No. Sumitomo Metal Industries, Ltd.

Claims (4)

[Claims] 1. A means for supplying a microwave, a reaction vessel having a microwave introduction window and a sample stage facing the microwave introduction window, a means for applying a high frequency to the sample stage, and an electric device facing the sample stage. A plasma processing apparatus having a counter electrode that is electrically grounded, wherein the counter electrode is provided inside a reaction vessel and at a peripheral portion of a microwave introduction window. 2. The plasma processing apparatus according to claim 1, further comprising a microwave adjusting plate made of metal having a microwave supply hole, which is provided in the vicinity of the outer surface of the reaction vessel of the microwave introducing window. 3. The plasma processing apparatus according to claim 1 or 2, further comprising a plasma focusing means formed of an annular dielectric material in the vicinity of the inner surface of the reaction vessel of the microwave introduction window. 4. A plasma processing method, which comprises subjecting a sample to plasma processing using the plasma processing apparatus according to any one of claims 1 to 3.