JPH08279493A - Plasma processing system - Google Patents

Abstract

PURPOSE: To set the ratio between the inductive coupling discharge component and capacitive coupling discharge component appropriately by disposing a pair of antenna bodies such that the induced fields are directed reversely from each other. CONSTITUTION: Two antenna bodies 50, 52 are disposed around a plasma generation chamber 40 made of quarts and fed with currents in reverse directions. Since the fields induced from the antenna bodies are weakened each other, the inductive coupling discharge component is reduced. Extent of reduction can be regulated by varying the distance between the antenna bodies 50, 52. Since the band plates 54, 55 of the antenna bodies 50, 52 are facing the plasma generation chamber 40, a planar antenna surface is provided thus increasing the area of a sheath formed closely to the inner wall of the plasma generation chamber 40. Consequently, the capacitive coupling discharge component is increased. The area of sheath depends on the width W of the band plates 54, 55.

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 for etching or film-forming a semiconductor device in a vacuum,
In particular, the present invention relates to a plasma processing apparatus having an improved antenna device for generating plasma.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional plasma processing apparatus having an inductively coupled plasma generating chamber. A coil-shaped antenna 12 is wound around the plasma generation chamber 10 formed of a dielectric material, and this antenna 12 generates an induction electric field in the plasma generation chamber 10 under reduced pressure. A high frequency power supply 16 is connected to one end of the antenna 12 via a matching box 14, and power is supplied from the high frequency power supply 16. The other end of the antenna 12 is normally grounded.

A case of plasma etching a wafer using this plasma processing apparatus will be described. A processing chamber 18 communicates with the plasma generation chamber 10, and the processing chamber 18
A substrate holder 20 is installed inside. The wafer 22 to be processed is placed on the substrate holder 20. A bias power source 24 is connected to the substrate holder 20,
The structure is such that the ion energy incident on the wafer 22 can be controlled.

FIG. 7 is a block diagram of a conventional plasma processing apparatus provided with a plasma generation chamber of a cathode coupling type which is a type of capacitive coupling type. A wafer to be processed 28 is placed on the cathode 26, and a high frequency power source 30 is connected to the cathode 26 to supply electric power for maintaining plasma generation. There is a counter electrode 32 facing the cathode 26, and the counter electrode 32 is grounded via a plasma generation chamber 34. In this cathode coupled type example, the plasma generation chamber 34 also serves as a processing chamber.

[0005]

Since the inductively coupled plasma generating chamber of FIG. 6 can discharge at a lower pressure than the capacitively coupled plasma generating chamber of FIG. 7, it is applied to etching. In this case, there is an advantage that good anisotropic etching can be realized. However, this inductive coupling type has a problem that the dissociation of the process gas proceeds too much. This problem will be described in detail below. FIG. 8 is a sectional view showing an electromagnetic field state in the plasma generation chamber 10 of FIG. When an alternating current flows through the coiled antenna 12, the magnetic field lines 36
Is induced, and this magnetic field line 36 fluctuates with time,
As a result, an annular induction electric force line 38 is generated. The line of induced electric force 38 is generated in the whole plasma bulk. In such a situation, when electrons move in the plasma, they are accelerated by this induction electric field, and the plasma generation chamber 1
Collide with the gas inside 0 many times to generate ions,
It causes dissociation and excitation of process gas. As a result, the process gas is excessively dissociated into its constituent atoms or even into an atomic group having a small number of atoms. If the dissociation of the process gas proceeds excessively in this way, it may be inconvenient for some processes. For example, in the case of plasma etching SiO ₂ , radicals in an intermediate dissociation state such as CF ₂ and CF ₃ are necessary. However, if the dissociation of the process gas proceeds too much, these radicals are not sufficiently obtained, which is sufficient. A high selection ratio to Si cannot be obtained.

By the way, in the inductive coupling type of FIG. 6, if the current supplied to the coiled antenna 12 is reduced,
The degree of ionization can be reduced. However, the dissociation of the process gas progresses throughout the plasma bulk because the induction electric field that accelerates the electrons exists throughout the plasma bulk. As a result, the dissociation degree of the process gas becomes higher than that of the capacitively coupled type. As described above, in the plasma processing apparatus including the inductively coupled plasma generation chamber, if the antenna current is simply reduced, for example, SiO ₂
It is impossible to obtain a sufficient selection ratio with respect to the underlying Si in the above etching.

On the other hand, in the capacitive coupling type of FIG. 7, ions accelerated mainly in the potential drop portion (so-called sheath) on the front surface of the cathode 26 collide with the cathode 26, and at that time, electrons are emitted by γ action, Plasma generation is maintained by these electrons. Usually, the thickness of this sheath is about several hundred μm to 10 mm. Since the generation of ions and radicals is limited in this thin sheath where electrons are accelerated, the number of times that electrons collide with the process gas is not so large, and as a result, higher order dissociation of the process gas does not proceed. Therefore, for example, in etching SiO ₂ , plasma containing a large amount of radicals in an intermediate dissociation state such as CF ₂ and CF ₃ can be obtained, and as a result, a high selectivity ratio to Si can be obtained. However, compared with the inductively coupled plasma generation chamber, the operating pressure is high, and therefore the anisotropic etching ability is poor, and there is a problem that a fine pattern of 0.25 μm or less cannot be etched.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a plasma processing apparatus having both an inductively coupled discharge component and a capacitively coupled discharge component. To provide. Another object of the present invention is to provide a plasma processing apparatus capable of adjusting the ratio of the inductively coupled discharge component and the capacitively coupled discharge component.

[0009]

The plasma processing apparatus of the present invention is characterized by an antenna device provided around the plasma generating chamber. That is, according to the present invention, an antenna device is arranged around a plasma generation chamber formed of a dielectric, and a current is passed through the antenna device to generate plasma inside the plasma generation chamber to process an object to be processed. In the plasma processing apparatus, the antenna device includes a pair of antenna bodies, and the magnetic field induced by one antenna body is in the opposite direction to the magnetic field induced by the other antenna body inside the plasma generation chamber. , These antenna bodies are connected to the power supply device.

The present invention can be applied in principle to any plasma processing apparatus as long as it can process an object to be processed using plasma. Typical examples of applicable plasma processing apparatuses include plasma etching, ashing, plasma surface treatment, and plasma CVD.

To describe a typical configuration, the plasma generating chamber has a cylindrical shape, and a pair of antenna units are arranged around the plasma generating chamber in the axial direction of the plasma generating chamber. In this case, it is effective to make the distance from the axial center position of one antenna body to the axial center position of the other antenna body, that is, the distance between the antenna centers smaller than the inner diameter of the antenna body. It is desirable that the distance between the centers of the antennas be adjustable. Further, it is preferable that the power feeding portion of one antenna body and the power feeding portion of the other antenna body are arranged so as to face each other with the plasma generation chamber interposed therebetween.

Explaining a preferable structure of the antenna body,
By including a strip-shaped plate facing the plasma generation chamber,
The strip-shaped plate surrounds the plasma generating chamber. And this strip | belt-shaped board is made to surround the circumference | surroundings of a plasma generation chamber substantially over 1 round.

The material of the plasma generating chamber is preferably selected as an optimum material according to the process carried out by the plasma processing apparatus. For processes where oxygen can be mixed in,
The material of the plasma generating chamber is preferably quartz. Aluminum oxide is preferable when a fluorine-based process gas is used, and aluminum nitride is preferable when it is desired to completely eliminate the influence of oxygen. When it is desired to eliminate the influence of oxygen and the influence of aluminum, silicon nitride is preferable.

In order to reduce the influence of sputtering of the plasma generating chamber, a magnetic field parallel to the inner wall surface of the plasma generating chamber may be applied near the inner wall surface.

[0015]

The pair of antenna bodies arranged so as to generate magnetic fields in opposite directions weaken each other's induced magnetic fields,
As a result, the induction field weakens. This means that the inductively coupled discharge component is weakened. The canceling action of this inductively coupled discharge component can be adjusted by adjusting the distance between the centers of the antennas. Further, if the strip-shaped plate of the antenna body faces the plasma generating chamber, the area of the sheath near the inner wall surface of the plasma generating chamber can be increased. This means that the capacitively coupled discharge component increases. This capacitively coupled discharge component can be adjusted by adjusting the width of the strip plate. If the ratio of the inductively coupled and capacitively coupled discharge components is optimized, for example, Si
In O ₂ plasma etching, high-speed etching and low-pressure discharge characteristics, which are advantages of an inductively coupled plasma processing apparatus, and high selectivity with respect to underlying Si, which is an advantage of a capacitively coupled plasma processing apparatus, It is possible to perform etching with both.

[0016]

1 is a block diagram of a plasma processing apparatus according to an embodiment of the present invention. The upper plasma generation chamber 40 and the lower processing chamber 42 are in communication with each other, and the target wafer 46 is placed on the substrate holder 44 in the processing chamber 42. The substrate holder 44 is connected to the bias power source 48.

The plasma generating chamber 40 made of quartz has a cylindrical shape, and its upper end has a substantially spherical shape. Two antenna bodies 50 and 52 are arranged around the plasma generation chamber 40. The upper antenna body 50 includes an arc-shaped strip plate 54 facing the plasma generation chamber 40, and an arc-shaped water cooling pipe 56 brazed to the outer surface of the strip plate 54. The strip 54 and the water cooling pipe 56 are made of a conductor.
As shown in the plan view of FIG. 2, the strip plate 54 and the water cooling pipe 56 surround the plasma generating chamber 40 for almost one round, and are cut at one place 58 on the circumference. Therefore, the upper antenna body 50 is a so-called one-turn antenna. Cooling water flows inside the water cooling pipe 56. The lower antenna body 52 also includes a strip plate 55 and a water cooling pipe 57 that have the same shape as the upper antenna body 50.

FIG. 2 is a plan view showing the shapes and arrangement of the two antenna bodies. The upper antenna body 50 and the lower antenna body 52 are arranged such that their cut positions are opposite to each other. That is, in the upper antenna body 50, there is a cut portion 58 on the right side in FIG. 2, and in the lower antenna body 52, there is a cut portion 60 on the left side. In the upper antenna body 50, the water cooling pipe 56 on one end side of the cut point 58.
Are connected to a high frequency power supply 64 via a matching box 62. The strip plate 54 on the other end side of the cutting point 58 is grounded. Further, in the lower antenna body 52, the water cooling pipe 57 on one end side of the cut portion 60 is provided in the matching box 6.
It is connected to the high frequency power supply 64 via 2, and the strip plate 55 on the other end side is grounded. The water cooling pipes 56, 57 have cooling water inlets 66, 68 and outlets 67, 69.

In the present embodiment, as shown in FIG. 2, the cut portion 58 of the upper antenna body 50 and the cut portion 60 of the lower antenna body 52 serve as power feeding portions, and these power feeding portions sandwich the plasma generating chamber. It is arranged to face each other. By the way, since a strong electric field is generated in the feeding part of the antenna body, the plasma density is locally high in the vicinity of the feeding part, but by arranging the two feeding parts on opposite sides as in this embodiment, The higher plasma density is relaxed and dispersed. Thereby, more uniform plasma can be obtained.

The two antenna bodies 50 and 52, the high frequency power source 64 and the ground are connected so that the directions of the currents flowing through the antenna bodies 50 and 52 are opposite to each other. For example, in FIG. 2, when a current flows in the upper antenna body 50 in a clockwise direction when viewed from above as indicated by an arrow 70 at a certain moment, a current flows in the lower antenna body 52 in a counterclockwise direction as indicated by an arrow 71.

Next, a method of etching SiO ₂ using the plasma processing apparatus shown in FIG. 1 will be described. First, in FIG. 1, the wafer 46 to be processed is placed on the substrate holder 44.
And the plasma generation chamber 40 and the processing chamber 42 are exhausted by an exhaust system (not shown). Next, the processing chamber 4 is controlled by a gas supply system (not shown) while controlling the flow rate of the process gas such as CHF ₃ and C ₄ F ₈ through the mass flow controller.
Supply to 2. Next, the variable orifice between the processing chamber 42 and the exhaust system is controlled by the pressure control controller to keep the pressure in the processing chamber 42 within the range of 1 to 100 mTorr. Next, power is supplied from the high frequency power source 64 to the two antenna bodies 50 and 52 via the matching box 62. At the same time, the substrate holder 44 has a bias power supply (high frequency power supply) for controlling the incident energy of ions.
Power is supplied from 48. Plasma is generated inside the plasma generation chamber 40, and the process gas is dissociated into radicals such as CF ₂ and CF ₃ and diffused toward the processing chamber 42. The SiO ₂ on the wafer 46 is etched by the radicals.

Next, a mechanism capable of controlling the ratio of the inductively coupled discharge component and the capacitively coupled discharge component in the plasma processing apparatus shown in FIG. 1 will be described. FIG. 3 shows a plasma generation chamber 40.
It is an explanatory view showing the state of the electromagnetic field inside. It is assumed that a clockwise current as shown by an arrow 70 in FIG. 2 is flowing in the upper antenna body 50 at a certain moment, and this current is increasing with time. Then, due to this current, a downward induced magnetic force line 72 is generated. Moreover, since the current flowing through the upper antenna body 50 is increasing, the magnetic flux density of the induced magnetic force lines 72 is also increased, and the induced electric force lines 74 are generated in the direction (counterclockwise direction when viewed from above) to prevent the time fluctuation. To do. On the other hand, since a current flowing in the lower antenna body 52 in the opposite direction to that of the upper antenna body 50 flows, the lower antenna body 52 causes an upward magnetic field line 73 of upward induction and a clockwise electric field line 75 of induction when viewed from above. appear.

By the way, when the upper antenna body 50 and the lower antenna body 52 are close to each other to a certain extent, the induced magnetic fields generated by the upper antenna body 50 and the lower antenna body 52 are weakened because they are opposite to each other, and as a result, the net induced electric field decreases. . This reduces the degree of inductive coupling. The degree to which the induced magnetic fields cancel each other can be adjusted by changing the distance between the two antenna bodies 50 and 52. In addition, in the intermediate surface 76 between the upper antenna body 50 and the lower antenna body 52,
The components of the induced magnetic field that cross this plane vertically cancel each other out to zero.

On the other hand, since the strip plates 54 and 55 of the antenna bodies 50 and 52 face the plasma generating chamber 40,
Since the antenna has a planar antenna surface, the areas of the sheaths 78 and 79 formed in the vicinity of the inner wall surface of the plasma generation chamber 40 can be increased as compared with the conventional coil having a circular cross section.
This increases the degree of capacitive coupling. Sheath 7
The areas of 8, 79 can be optimized by adjusting the width W of the strips 54, 55.

FIG. 4 is a graph showing the radial distribution of the induced magnetic field strength in the plasma generation chamber. The vertical axis represents the intensity of the induced magnetic field component that crosses the central plane 80 (see FIG. 3) in the axial direction of the upper antenna body 50, and the horizontal axis represents the distance from the center of the chamber (plasma generation chamber). is there. The magnetic field induced by the upper antenna body 50 has a maximum axial component of the induced magnetic field at the center plane 80. This graph shows that the inner diameter D of the antenna body is 100 mm, the width W of the antenna body is 10 mm, the thickness t of the antenna body is 1 mm, the coil current is a direct current of 10 A, and the distance d between the centers of the two antenna bodies is 20 to 100 mm. It is calculated and calculated under the condition of. This graph shows the center plane 80 of the upper antenna body 50.
However, the same graph is obtained on the center plane of the lower antenna body 52.

As can be seen from this graph, the induced magnetic field strength decreases as the distance d between the antenna centers is decreased (that is, the two antenna bodies are brought closer to each other). In particular, the induced magnetic field strength at the center of the plasma generation chamber (position at a distance of 0 mm from the chamber center) is greatly reduced. Since the induction electric field strength is proportional to the product of the induced magnetic field strength and the degree of change over time according to the teaching of Faraday's induction law, it is a problem in an electromagnetic field system that fluctuates at a constant frequency. If the intensity of the induced magnetic field that crosses the plane perpendicular to the plane is small, the induced electric field is also small.

In FIG. 4, an example of calculation when only one antenna body is provided is also shown as "1 coil". The curve below this "1 coil" curve is a calculation example when the distance d between the centers of the two antenna bodies is 100 mm (that is, the distance d between the antenna centers is equal to the inner diameter D of the antenna body). Is. In this way, the curve of the induced magnetic field strength for one coil and the curve of the induced magnetic field strength for d = 100 mm are very close to each other, so even if two antenna bodies are provided, It can be seen that if the distance between the centers of the antennas is made larger than the inner diameter of the antenna body, the effect of reducing the induced magnetic field strength by providing two antenna bodies can hardly be expected. That is,
If the two antenna bodies are too far apart from each other, the expected interaction will almost disappear. Therefore, the distance between the centers of the antennas needs to be smaller than the inner diameter of the antenna body.

As described above, in this embodiment, the degree of the inductively coupled plasma state can be controlled by adjusting the distance d between the antenna centers in FIG. 3, while the antenna width W is adjusted. As a result, the degree of the capacitively coupled plasma state can be controlled. As a result, SiO
_In plasma etching that requires an etchant in an intermediate dissociation state, such as ₂ etching, it is possible to achieve both high-speed etching, which is an advantage of inductive coupling, and high selectivity to the base, which is an advantage of capacitive coupling. Becomes That is, when the distance d between the antenna centers is increased and the antenna width W is decreased, the inductive coupling in the plasma state becomes superior to the capacitive coupling. In this state, excessive dissociation of the process gas proceeds, and high-speed etching and low-pressure discharge characteristics can be obtained. However, it is impossible to obtain a high selection ratio with respect to the underlying Si. On the other hand, when the distance d between the antenna center planes is reduced and the antenna width W is increased, the capacitive coupling in the plasma state becomes superior to the inductive coupling. In this state, a plasma rich in CFx radicals in an intermediate dissociation state can be obtained, but there are problems in terms of etching rate and operating pressure. Therefore, by appropriately adjusting the distance d between the antenna centers and the antenna width W, etching having both high-speed etching and low-pressure discharge characteristics and high selectivity with respect to the underlying Si becomes possible.

Next, the material of the plasma generating chamber will be described. When the capacitively-coupled discharge component increases, the degree to which ions collide with the inner wall surface of the plasma generation chamber and sputter it increases. This means that the material components of the plasma generation chamber are mixed in the plasma atmosphere. Therefore, even if such mixing occurs, it does not significantly affect the process performed in the plasma processing apparatus,
The material of the plasma generating chamber must be appropriately selected according to the process.

For example, in a process in which oxygen is mainly used as a process gas, or a process in which mixing of oxygen is not a problem, that is, a multilayer resist process, ashing, a post-treatment process of SiO ₂ , etc. It is desirable to use the plasma generation chamber of The quartz plasma generating chamber is excellent in terms of thermal shock resistance, high purity (small inclusion of impurities), low price, and the like.

When a fluorine-based process gas is used, a plasma generation chamber made of aluminum oxide is desirable. For example, normal alumina (Al ₂ O ₃ ) or polycrystalline alumina (translucent alumina) can be used. In this case, even if aluminum is mixed in the plasma to form a fluoride of aluminum, the fluoride is non-volatile, so that the influence of oxygen can be reduced as compared with the case of using quartz. When it is desired to completely eliminate the influence of oxygen, it is preferable to use aluminum nitride (AlN) as the material of the plasma generating chamber.

When the influence of oxygen is not permitted and the mixing of aluminum atoms and its compounds is not permitted in order to remove the adverse effects such as the doping of impurities into the residue and the wafer, silicon nitride ( It is preferred to use SiN).

As a method of reducing the influence of sputtering of the plasma generating chamber, a magnetic field (for example, an axial magnetic field) parallel to the inner wall surface is externally applied to the sheath portion near the inner wall surface of the plasma generating chamber. Is effective.
FIG. 5 shows an embodiment in which such an external magnetic field is applied.
That is, a pair of magnetic field generating coils 84 are arranged around the plasma generating chamber, and a direct current is passed through the coils 84 to generate a steady external magnetic field 82. The external magnetic field 82 becomes a magnetic field substantially in the axial direction at the sheaths 78 and 79. The inner wall surface of the plasma generation chamber formed of a dielectric material has a floating potential with respect to the bulk plasma, but when the above-mentioned external magnetic field 82 is applied thereto, electrons are trapped in this external magnetic field 82. Therefore, the necessary repelling potential becomes smaller (the electric field near the inner wall surface of the plasma generation chamber is a negative potential with respect to the plasma,
This negative potential is called the repelling potential because it repels electrons from the wall). As a result, the ion energy incident on the inner wall surface of the plasma generation chamber is reduced, and the sputtering of the inner wall surface is reduced. Further, since the plasma diffusion is suppressed by the external magnetic field, the plasma density is increased, and as a result, the etching rate is improved. In this embodiment, the strength of the steady external magnetic field 82 at the sheaths 78, 79 is about 50 gauss or more,
This has the effect of suppressing the sputtering of the inner wall surface far more than the fluctuating magnetic field (about 6 Gauss) generated by the antenna at the sheaths 78 and 79.

In the embodiments described so far, each of the two antenna bodies is a one-turn antenna. However, even if each of the antenna bodies is composed of a coil-shaped antenna body having a plurality of turns, The invention is effective.

[0035]

According to the present invention, since the magnetic fields induced by the pair of antenna bodies are opposite to each other, the inductively coupled discharge component is reduced, and excessive dissociation of the process gas can be prevented. By adjusting the distance between the antennas, the canceling action of the magnetic field can be adjusted, and the degree of the inductively coupled discharge component can be adjusted. Further, by adjusting the width of the antenna body, the sheath area in the vicinity of the inner wall surface of the plasma generation chamber can be adjusted, and the capacitively coupled discharge component can be adjusted. By optimizing the ratio of the inductively-coupling and capacitively-coupling discharge components, for example, in plasma etching of SiO ₂ , it is possible to perform etching having both high-speed etching, low-pressure discharge characteristics, and high selectivity with respect to underlying Si.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of an antenna body.

FIG. 3 is an explanatory diagram showing an electromagnetic field in a plasma generation chamber.

FIG. 4 is a graph showing a radial distribution of induced magnetic field strength in a plasma generation chamber.

FIG. 5 is an explanatory diagram of an example in which an external magnetic field is applied.

FIG. 6 is a configuration diagram of a conventional inductively coupled plasma processing apparatus.

FIG. 7 is a configuration diagram of a conventional capacitively coupled plasma processing apparatus.

8 is a cross-sectional view showing an electromagnetic field in a plasma generation chamber of the conventional apparatus of FIG.

[Explanation of symbols]

 40 Plasma Generation Chamber 42 Processing Chamber 44 Substrate Holder 46 Wafer 50 Upper Antenna Body 52 Lower Antenna Body 54, 55 Strip Plates 56, 57 Water Cooling Pipe 64 High Frequency Power Supply

Claims (12)

[Claims] 1. An antenna device is arranged around a plasma generation chamber formed of a dielectric material, and a current is passed through the antenna device to generate plasma inside the plasma generation chamber to process an object to be processed. In the plasma processing apparatus, the antenna device includes a pair of antenna bodies, and the magnetic field induced by one antenna body is in the opposite direction to the magnetic field induced by the other antenna body inside the plasma generation chamber, A plasma processing apparatus in which these antenna bodies are connected to a power supply device. 2. The plasma generation chamber has a cylindrical shape, and the pair of antenna bodies are arranged side by side in the axial direction of the plasma generation chamber around the plasma generation chamber. Plasma processing equipment. 3. The plasma according to claim 2, wherein the distance between the centers of the antennas from the axial center position of one antenna body to the axial center position of the other antenna body is smaller than the inner diameter of the antenna body. Processing equipment. 4. The plasma processing apparatus according to claim 1, wherein the distance between the centers of the antennas is adjustable. 5. The plasma processing apparatus according to claim 1, wherein the power feeding portion of one antenna body and the power feeding portion of the other antenna body face each other with the plasma generating chamber interposed therebetween. 6. An antenna device is arranged around a plasma generation chamber formed of a dielectric material, and a current is passed through the antenna device to generate plasma inside the plasma generation chamber to process an object to be processed. In the plasma processing apparatus, the antenna device includes a pair of antenna bodies, and the magnetic field induced by one antenna body is in the opposite direction to the magnetic field induced by the other antenna body inside the plasma generation chamber, These antenna bodies are connected to a power supply device, and the antenna body includes a strip-shaped plate facing the plasma generation chamber, and the strip-shaped plate surrounds the plasma generation chamber. Processing equipment. 7. The plasma processing apparatus according to claim 6, wherein the strip-shaped plate surrounds the circumference of the plasma generation chamber substantially for one round. 8. The plasma processing apparatus according to claim 6, wherein the material of the plasma generating chamber is quartz. 9. The plasma processing apparatus according to claim 6, wherein the material of the plasma generating chamber is aluminum oxide. 10. The plasma processing apparatus according to claim 6, wherein the material of the plasma generating chamber is aluminum nitride. 11. The plasma processing apparatus according to claim 6, wherein the material of the plasma generating chamber is silicon nitride. 12. Near the inner wall surface of the plasma generation chamber,
The plasma processing apparatus according to claim 6, wherein a magnetic field parallel to the inner wall surface is applied.