JP2001230234A - Apparatus and method for plasma treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a problem of forming a thick deposit film by adhering a reaction product or the like to a wafer mounting electrode side face when plasma etching is repeated. SOLUTION: A replaceable member for forming a deposit film is installed on an outer periphery of a wafer mounting electrode to suppress a formation of the deposit film on the side face of the wafer mounting electrode. A size of the member for the suppression is smaller than an outer diameter of the wafer, and an interval to a rear surface of the wafer is 0.3 mm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a plasma processing method and a plasma processing apparatus for processing an insulating film such as a silicon oxide film.

[0002]

2. Description of the Related Art A conventional technique relating to an etching apparatus and an etching method for an insulating film (hereinafter simply referred to as an oxide film) such as a silicon oxide film is disclosed in JP-A-52-114444. It is based on sputter etching using freon gas as the main component. As an etching gas, a gas species composed of fluorine, carbon, hydrogen, oxygen and the like diluted with argon is generally used. That is, it is a method of obtaining excellent etching characteristics by setting these etching gas species to an optimum composition, and various specific methods have been proposed.

[0003] Etching of an oxide film proceeds by reacting silicon with fluorine to form silicon fluoride. However, since selective etching of polysilicon or silicon nitride as a base of the oxide film is required, the oxide film is etched. Then, the etching proceeds, but the etching must be stopped for the base material. Therefore, etching is performed using CF radicals and ions. Thus, the fluorine F of the CF radical reacts with silicon on the surface of the oxide film and is vaporized. Also, CF
Carbon C of the system radical reacts with oxygen in the oxide film and is removed. On the other hand, in the film of polysilicon or silicon nitride, C
Since it does not contain an element that reacts with the carbon C of the F-based radical and evaporates, it remains as a deposition film on the surface. This deposition film suppresses etching, and enables selective etching of the oxide film and the base material.

[0004] Since such an etching mechanism is used, in the above-described oxide film etching method, CF is not limited to the wafer surface but also to the inner wall of the etching chamber and the surface of the wafer electrode.
A deposition film of the system gas is formed. During the etching, the wafer is fixed on the electrode mounting surface, so that no deposition film is formed on the electrode mounting surface, but a deposition film is formed on the outer peripheral portion of the electrode mounting surface, and the etching is repeated. It gradually becomes thicker. If the deposited film is too thick, the film may be peeled off or cracked, and the deposited film may adhere to the wafer mounting surface and cause a problem that the wafer is not properly supported.

Therefore, in the conventional method, when the apparatus is periodically opened to the atmosphere and cleaned, the deposition film on the outer peripheral portion of the electrode mounting surface is removed. However, if the electrostatic chuck method is used to support the wafer, the electrostatic chuck film is formed on the electrode surface, and the latest care must be taken to prevent damage to the electrostatic chuck film when removing the deposition film. Therefore, there is a problem that the maintainability is reduced.
Further, when the deposit film is firmly adhered, the electrode must be disassembled and cleaned, but this requires a lot of time and has a problem that the maintainability is impaired.

Conventionally, as an electrode structure of this type of etching apparatus, for example, there is one described in JP-A-10-303288. In this electrode, in order to prevent the wafer temperature from changing at the outer peripheral portion of the wafer, a member installed on the outer peripheral portion of the wafer mounting surface is electrostatically adsorbed, and a gas is introduced into the adsorbing surface to control the temperature of the member. ing. However, no consideration is given to deposits.

In the electrode described in US Pat. No. 5,805,408, a member having a spring property is provided on the outer periphery of the wafer mounting surface to prevent the heat transfer gas introduced into the back surface of the wafer from leaking to the outside. This prevents the back surface introduction gas (helium gas) from being mixed into the etching gas, and prevents the etching gas from entering the outer periphery of the electrode. However, in this example, when the spring member is in contact with the back surface of the wafer, and an etching gas or a reaction product adheres to the plasma side surface of the spring member to form a deposition film, the deposition on the surface of the spring member is performed. An object may adhere to the back surface of the wafer.

[0008]

As described above, in the conventional plasma etching apparatus, no special consideration has been given to deposits adhering to the outer peripheral portion of the wafer mounting surface. However, etching of an insulating film such as an oxide film or a low dielectric constant material (Low-k) is a depolitic etching using a CF-based gas. Therefore, a large amount of the deposited film adheres to the outer peripheral portion of the wafer mounting electrode surface. If a large amount of this deposition film adheres, the deposition film adheres to the wafer mounting surface, and in the case of an electrostatic chucking electrode, poor suction may occur.

As described above, in the conventional apparatus, some countermeasures are required for forming a deposited film on the outer peripheral portion of the wafer mounting surface.

An object of the present invention is to suppress a deposition film adhering to an outer peripheral portion of a wafer mounting surface and to prevent a deposited material from wrapping around the wafer mounting surface.

It is another object of the present invention to suppress deposits on an electrode supporting a wafer in plasma processing, particularly in plasma etching processing, to prevent generation of foreign matter, and to improve the operation rate.

Another object of the present invention is to simplify a cleaning operation such as removing a deposit film adhered to an outer peripheral portion of a wafer mounting electrode during cleaning of a plasma etching apparatus, and to improve maintainability.

[0013]

SUMMARY OF THE INVENTION The present invention is characterized by a vacuum processing chamber, a sample stage on which a sample to be processed in the vacuum processing chamber is mounted, plasma generating means, and a gas supply for generating plasma. Means, and a plasma processing apparatus having a bias means for applying a high-frequency bias to the sample independently of the means for generating the plasma, wherein the sample stage has a substantially flat sample support surface supporting the sample and a periphery thereof. The present invention has a concave outer peripheral surface receding from the sample support surface, and an annular deposit suppressing member is detachably mounted on the concave outer peripheral surface of the sample stage adjacent to the outer periphery of the sample support surface. .

According to another feature, the gap between the deposit suppressing member and the rear surface of the wafer is set to 0.5 mm or less, preferably 0.3 mm or less so that an etching gas or a reaction product does not easily enter the wafer mounting surface. The following is assumed. However, it is assumed that the present deposit suppressing member does not contact the rear surface of the wafer. In addition, the outer diameter of the surface of the present deposit suppressing member facing the back surface of the wafer shall not exceed the diameter of the wafer. Further, a protective member for preventing the electrodes from being damaged by plasma and for improving the etching characteristics is provided on the outer peripheral portion of the deposit control member.

When the etching is repeated with the above configuration, a deposit film is formed on the side surface of the deposit suppressing member. However, formation of a deposited film on the outer peripheral side surface of the wafer mounting surface is suppressed. Since the deposit suppressing member is exchangeable, when the etching chamber is opened to the atmosphere and cleaned, if the electrode is replaced with another deposited suppressing member which has been cleaned in advance, the electrode cleaning time can be reduced to a minimum.

As described above, according to the present invention, when the etching chamber is opened to the atmosphere and cleaned, the labor for cleaning the wafer mounting electrode is greatly improved, so that the maintainability and the operation rate of the apparatus are improved. improves.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a schematic diagram of a plasma etching apparatus to which the present invention is applied, which is a plasma processing apparatus to which electron cyclotron resonance is applied. Electron cyclotron resonance (ECR) around etching chamber 1, which is a vacuum vessel
A coil 2 is provided for generating a magnetic field for use. The etching gas is supplied through a gas supply pipe 3 and several hundreds of fine holes having a diameter of about 0.4 to 0.5 mm are formed.
The gas is introduced into the etching chamber 1 from a gas supply plate 4 made of silicon or glassy carbon provided in about pieces. A disk-shaped antenna 5 that emits UHF-band microwaves is provided above the gas supply plate 4, and the microwaves to the antenna 5 are supplied from a power source 6 through a matching circuit 7 and an introduction shaft 8. The microwave is radiated from around the antenna 5, and a resonance electric field in a space above the antenna 5 is introduced into the etching chamber through the dielectric 9. As the frequency of the microwave, a band capable of lowering the electron temperature of the plasma from 0.25 eV to 1 eV is selected.
The range is from 0 MHz to 1 GHz. In this embodiment, 45
0 MHz was used. The dielectric 9 is made of quartz,
Alumina can be used in addition to quartz, and a heat-resistant polymer such as polyimide having a small dielectric loss can be used.

A wafer mounting electrode 1 is provided below the gas supply plate 4.
0 is provided, and the wafer 11 is supported by electrostatic attraction (power supply for electrostatic attraction is not shown). A high frequency bias is applied to the wafer mounting electrode 10 from the high frequency power supply 12 to attract ions in the plasma to the wafer 11.

The wafer mounting electrode 10 has a vertical mechanism for transferring the wafer and setting the distance between the electrodes, but is omitted in FIG. In addition, the wafer mounting electrode 10
The rectangular part shown in white is a flow path for flowing a refrigerant for temperature control, but the temperature controller for it is also omitted.

The temperature of the inner wall 13 of the etching chamber is controlled. By introducing the temperature-controlled refrigerant to the inner wall 13, the inner wall 13 is maintained at a constant temperature. In this embodiment, the temperature is set to 30 ° C.

A concave portion is formed on the outer peripheral portion of the wafer mounting surface of the wafer mounting electrode 10, and a deposit ring 14 as a deposit suppressing member is provided thereon. A susceptor 15 as a protection member is provided on the outer periphery of the deposition ring 14 to prevent the electrode 10 from being damaged by plasma. Helium gas is supplied to the back surface of the wafer 11 through the back surface gas supply hole 16, and the temperature of the wafer is controlled by gas heat transfer.

Deposit ring 14 as deposit control member
Can be quartz, alumina, or aluminum nitride.
Silicon and silicon nitride can also be used, but etching with radicals in plasma is not preferable because the life is shortened. Further, a heat-resistant polymer material such as polyimide can also be used. Further, a depot ring 14 is manufactured from aluminum, and the surface is coated with a heat-resistant polymer material such as polyimide, a material such as silicon or silicon oxide, or anodized to form aluminum oxide on the surface. You may.

The susceptor 15 serving as a protective member may be made of the same material as that of the deposition ring 14, or a material suitable for the reaction with radicals in the plasma.

A vacuum chamber directly connected to the etching chamber 1 is provided with a turbo-molecular pump having a pumping speed of about 2000 to 3000 L / s. Although not shown in the figure, a conductance valve for adjusting the pumping speed is provided at the opening of the turbo-molecular pump, and the pumping speed is adjusted to achieve a flow rate and a pressure suitable for etching.
Further, a stop valve is provided for isolating the turbo-molecular pump at the time of opening to the atmosphere.

Next, FIG. 2 shows details of the wafer mounting electrode portion of the plasma etching apparatus. FIG. 4 shows a conventional wafer mounting electrode shown for comparison.

The wafer mounting surface 10a of the wafer mounting electrode 10
An outer peripheral recessed portion is formed in contact with the outer peripheral side surface, and a depot ring 14 as a deposit control member is installed on the outer peripheral concave portion. The gap 11a between the deposit ring 14 and the back surface of the wafer 11 is set to 0.3 mm or less. The outer diameter of the depot ring 14 facing the rear surface of the wafer is
1 is set smaller than the outer diameter. However, wafer 1
The area where 1 protrudes from the electrode mounting surface 10a is 2-3.
mm, the surface of the deposition ring 14 facing the rear surface of the wafer is also as narrow as 1 to 2 mm. Therefore, depot ring 1
In order to secure the rigidity of the wafer 4, the plane opposite to the wafer-facing surface is made larger than the outer diameter of the wafer 11, and L as shown in FIG.
It is a cross section. By doing so, the depot ring 14
Dimensional accuracy and dimensional stability are ensured.

A susceptor 15 as a protection member is provided outside the depot ring 14. The inner peripheral portion of the susceptor 15 is made to enter inside from the back surface of the wafer.

In the configuration shown in FIG. 2, the gap 11a between the deposit ring 14 and the back surface of the wafer is 0.3 mm or less, and the gap 15a between the inner peripheral portion of the susceptor 15 and the back surface of the wafer is set to about 0.3 mm. You. However, as the plasma etching is repeated, the inner peripheral portion of the susceptor 15 is consumed. Therefore, the gap 15a becomes gradually larger even if the initial value is 0.3 mm, and becomes 0.3 mm or more. At the same time, the amount of depot components, such as reaction products, which enter the depot ring 14 from the plasma through the gap 15 a increases, and a depo film is formed on the outer peripheral surface of the depot ring 14. However, since the deposition 14 is not exposed to ions in the plasma, the plasma consumption is very small. Therefore, the gap 11a between the deposition ring 14 and the back surface of the wafer is kept constant. When the gap 11a is maintained in a narrow state, the ratio of the deposition film formed on the outer peripheral side surface of the wafer mounting surface 10a through the gap 11a is sufficiently small.

On the other hand, in the conventional embodiment, as shown in FIG. 4, when the susceptor 15 is consumed as the etching is repeated, the gaps 15a and 11a are widened, and the incidence of the reaction product from the plasma is increased. I do. As a result, a deposition film is formed on the outer peripheral side surface of the wafer mounting surface 10a.

The dielectric film 10b is formed on the surface of the wafer mounting electrode 10 including the wafer mounting surface 10a and the outer peripheral concave portion.
Is formed. In this embodiment, the dielectric film 1 is used to support the wafer 11 on the wafer mounting surface 10a by the electrostatic attraction method.
Ob was an alumina film containing titanium oxide.

The following is an example of a plasma etching process using the present invention. Although not shown in the drawing, a wafer is carried into the etching chamber 1 evacuated to a high vacuum from a transfer chamber by a transfer arm, and is transferred onto the wafer mounting electrode 10. After the transfer arm retreats and the valve between the etching chamber 1 and the transfer chamber is closed, the wafer mounting electrode 10 rises and stops at a position suitable for etching. In the case of this embodiment, the distance (inter-electrode distance) between the wafer 11 and the gas introduction plate 4 is variable between 50 mm and 100 mm, but is set to 70 mm.

A silicon oxide film is formed on the wafer surface, the base is silicon nitride, and the mask is a photoresist. Ar and C ₄ F ₈ , O ₂ as etching gas
, And flow rates of 500, 10, 5
sccm was introduced. The pressure is 2 Pa. The output of the UHF microwave power supply was 1 kW, and the output of the bias power supply 12 to the wafer was 600 W. A current is applied to the coil 2 and a resonance magnetic field of UHF microwave 450 MHz of 0.01 MHz is applied.
6T was generated between the gas supply plate 4 and the wafer mounting electrode 10 (that is, the wafer 11). Next, the microwave power supply 6 was operated. Electron cyclotron resonance generates strong plasma in an ECR region with a magnetic field strength of 0.016T.

In order to make the etching characteristics uniform, it is necessary to make the incident ion density on the surface of the wafer 11 uniform. However, since the ECR position can be freely adjusted by the magnetic field coil 2, the optimum ion density is obtained. A distribution is obtained.
In the present embodiment, the shape of the ECR region is made to protrude toward the wafer 11, and the ECR region is formed at a position 50 mm above the wafer center line.

After the plasma is ignited, the high frequency power supply 12
A high voltage is applied to the wafer mounting electrode 10 from the electrostatic chuck DC power supply 17 connected in parallel to the wafer 11, and the wafer 11 is electrostatically attracted to the wafer mounting electrode 10. Helium gas is introduced to the back surface of the wafer 11 electrostatically adsorbed, and the temperature of the wafer is adjusted between the wafer mounting surface 10a of the wafer mounting electrode 10 and the wafer whose temperature has been adjusted by the coolant, via the helium gas. In this embodiment, the coolant temperature of the wafer mounting electrode 10 was set to 50 ° C.

Next, the high-frequency power supply 12 is operated to apply a high-frequency bias to the wafer mounting electrode 10. Thereby, ions are vertically incident on the wafer 11 from the plasma. High energy ion incidence is indispensable in the oxide film etching. In this embodiment, the high frequency bias voltage Vpp is also used.
(Voltage between the maximum peak and the minimum peak) was 1400V.

As soon as the bias voltage is applied to the wafer 11, the etching starts. The etching is completed at a predetermined etching time checked in advance. Alternatively, although not shown, a change in plasma emission intensity of the reaction product is monitored, an etching end point is determined to determine an etching end time, and after performing appropriate over-etching,
End the etching. The end of the etching is when the application of the high frequency bias voltage is stopped. At the same time, the supply of the etching gas is stopped.

Next, a step of detaching the electrostatically adsorbed wafer 11 from the wafer mounting electrode 9 is required, and argon or a gas type actually used for etching is used as a charge eliminating gas. After the supply of the electrostatic chucking voltage is stopped and the power supply line is connected to the ground, a charge elimination time of about 10 seconds is provided while maintaining the microwave discharge. Thereby, the electric charge on the wafer 11 is removed to the ground through the plasma,
The wafer 11 can be easily detached. When the charge elimination step is completed, the supply of the charge elimination gas is stopped and the supply of the microwave is also stopped. Further, the current supply to the coil 2 is also stopped. Further, the height of the wafer mounting electrode 10 is lowered to the wafer transfer position.

Thereafter, the etching chamber 1 is evacuated to a high vacuum for a while. When the high vacuum evacuation is completed, the valve between the transfer chambers is opened, the transfer arm is inserted, and the wafer 11 is removed.
And take it out. If there is next etching,
A new wafer is loaded and etching is performed again according to the above-described procedure.

The typical flow of the etching process has been described above. This process is repeatedly performed. As the number of processed wafers increases, a deposited film is formed.

In this embodiment, the gap 11a is set to 0.2 m
As a result, about 1 μm
m / h. Actually, the deposition film is not formed on the entire side surface of the deposition shield 14, but is more at the corner portion on the back surface side of the wafer, and there is less deposition film below. In this embodiment, since the etching chamber 1 was opened to the atmosphere and cleaned in a discharge time of about 100 hours, a deposition film of about 0.1 mm was formed. If this is the case, the deposit shield 14
No deposition film adhered to the back surface of the wafer or scattered on the wafer mounting surface 10a. But,
The formation of the deposit film more than this may hinder the electrostatic adsorption of the wafer 11 to the electrode 10. Therefore, the deposit shield 14 was replaced at the time of cleaning. Replacement time is short and maintenance is easy. The deposit shield 14 to which the deposit film has adhered can be removed by ultrasonic cleaning with an organic solvent such as alcohol. If a replacement part is prepared, the etching chamber 1 can be cleaned separately from the case where the etching chamber 1 is opened to the atmosphere and cleaned, which is efficient.

FIG. 3 shows another embodiment of the present invention. The active species consuming member 1 is provided on the outer peripheral portion of the wafer 11 mounted on the wafer mounting electrode 10 and outside the deposition shield 14 via a gap.
5b is provided. In the case of FIG. 3, a susceptor 15c is provided on the outer periphery of the active species consuming member 15b. The susceptor 15c is made of quartz or alumina. When the active species is fluorine, silicon, glassy carbon, silicon nitride, or the like is used for the active species consuming member 15b. The active species consuming member 15b is connected to the wafer mounting electrode 10 at a high frequency, so that a high frequency bias applied to the wafer 11 is applied. The active species consuming member 15b is consumed because it reacts with the active species during etching.
At the same time, the gap 15a is widened, but since the gap 11a is kept narrow, it is possible to suppress the formation of a deposit film on the outer peripheral side surface of the wafer mounting surface 10a.

Incidentally, in the case of FIG.
b can be used not only for consumption of the active species in the plasma, but also simply as a divided susceptor 15. That is, the gap 15 a is formed by ions incident on the outer peripheral portion of the wafer 11.
The wear of the susceptor 15
Since it is disadvantageous in terms of cost to replace the battery, it is also possible to replace only the consumed portion.

Next, another embodiment of the present invention will be described. FIG.
3 is the same as that shown in FIG.
4 is fixed to the wafer mounting electrode 10 by electrostatic attraction. For that purpose, the contact surface between them is made flat. By doing so, the deposition shield 14 and the wafer mounting electrode 1
The thermal resistance with 0 is improved as compared with the case where electrostatic adsorption is not performed. Therefore, the temperature rise of the deposition shield 14 is suppressed. Further, the helium gas introduced to the back of the wafer is
The helium gas flows out of the outer peripheral portion of the wafer and passes through the gap 11a. When the gap 11a is 0.3 mm or less, preferably 0.2 mm or less, gas heat transfer characteristics between the deposition shield 14 and the back surface of the wafer are improved, and deterioration of the wafer temperature distribution due to a rise in the temperature of the back surface of the wafer can be suppressed.

Next, it will be shown that a particularly remarkable effect can be obtained in the etching of the oxide film and the dielectric film described above as the embodiment of the present invention. In the etching of the oxide film and the dielectric film, a gas containing fluorine is used. In the above-mentioned embodiment, C ₄ F ₈ was used. In order to carry out highly selective etching of the silicon nitride film and the oxide film with these gas systems, it is necessary to optimize the ratio of the etching active species and the deposition forming species and supply ions efficiently. If there is an excessive amount of fluorine in the etching active species, both are etched, and the selectivity decreases.

Therefore, in order to reduce the fluorine in the plasma, the active species consuming member 15b is formed of a material containing silicon or carbon, and is placed on the wafer mounting electrode 10 to apply a bias. Since the active species consuming member 15b reacts with fluorine, fluorine in the plasma is reduced. This allows
The etching characteristics can be improved. The fluorine consumption can be adjusted by the bias application amount, or by changing the area of the active species consuming member 15b. When such a function is imparted to the active species consuming member 15b, the gap 15a is also consumed by reacting with the fluorine. As a result, the gap 15a widens. If the gap 15a widens, if the deposit shield 1
Without 4, a deposition film would be formed on the side surface of the wafer mounting surface 10a. In the present invention, even if the gap 15a is widened, the deposition film adheres to the deposition shield 14, so that the deposition film on the side surface of the wafer mounting surface 10a is suppressed.

Although the present embodiment has been described on the assumption that a UHF type ECR plasma etching apparatus is used,
There is no problem with other plasma sources, and the present invention is not limited to the UHF type ECR plasma etching apparatus. Therefore, the present invention can be applied to inductive plasma devices other than microwaves.

[0047]

According to the present invention, the deposition film adhering to the outer peripheral portion of the wafer mounting surface can be suppressed by forming it on another replaceable member, that is, the deposit suppressing member, thereby facilitating maintenance. This has the effect. The present invention is effective for etching an oxide film or a dielectric film on which a deposition film is easily formed. In addition, it is possible to suppress the occurrence of defective electrostatic attraction of the wafer due to the scattering of the deposit on the wafer mounting surface. Accordingly, the maintenance time can be reduced and the long-term stability of the wafer fixing can be achieved, so that there is an effect that the overall operation rate can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a plasma etching apparatus to which the present invention is applied.

FIG. 2 is a diagram showing details of a wafer mounting electrode portion of the plasma etching apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing details of a wafer mounting electrode portion of a plasma etching apparatus according to another embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a conventional wafer mounting electrode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Etching chamber, 2 ... Coil, 3 ... Gas supply pipe, 4 ...
Gas supply plate, 5: antenna, 6: power supply, 7: matching box, 8: introduction axis, 9: dielectric, 10: wafer mounting electrode, 11: wafer, 12: power supply, 13: inner wall, 14 ...
Depot shield, 15: Susceptor, 16: Electrostatic power supply

Continued on front page F term (reference) 4G075 AA30 CA47 EB44 EC10 FB03 FB04 FB06 5F004 AA16 BA14 BA16 BB11 BB18 BB22 BB23 BB25 BB32 BC02 BC08 CA04 CB02 CB16 CB18 DA00 DA23 DA26 DB00 DB03 5F045 AA09 BB15

Claims (13)

[Claims] 1. A vacuum processing chamber, a sample stage on which a sample to be processed in the vacuum processing chamber is mounted, a plasma generation means, a gas supply means for plasma generation, and a means for generating the plasma. A plasma processing apparatus having a bias means for independently applying a high-frequency bias to the sample, wherein the sample stage has a substantially flat sample support surface for supporting the sample, and a concave outer periphery retreated from the sample support surface around the sample support surface. Surface
A plasma processing apparatus, characterized in that an annular deposit suppressing member is detachably mounted on the concave outer peripheral surface of the sample stage adjacent to the outer periphery of the sample support surface. 2. A plasma processing apparatus according to claim 1, wherein a distance between an upper surface of said deposit suppressing member provided on an outer periphery of said sample support surface and a rear surface of said sample is 0.5 mm or less, preferably 0.1 mm or less. A plasma processing apparatus having a diameter of 3 mm or less. 3. The plasma processing apparatus according to claim 1, wherein a surface of said deposit suppressing member facing said sample back surface is smaller than an outer diameter of said sample, and a further outer periphery of said deposit suppressing member. Another protective member is provided on the concave outer peripheral surface so that the sample stage does not come into contact with plasma. 4. The plasma processing apparatus according to claim 1, wherein the material of the deposit suppressing member is a heat-resistant polymer material, quartz, silicon, silicon nitride, aluminum oxide, aluminum nitride. A plasma processing apparatus, which is made of any one of a material, glassy carbon, and a composite material such as an aluminum alloy coated on the surface with the above material. 5. The plasma processing apparatus according to claim 1, wherein the temperature of the sample stage is adjusted, and the temperature of the sample is adjusted by introducing a heat transfer gas to the back surface of the sample. The heat transfer gas introduced to the back surface of the sample and leaking to the outside from the outer peripheral portion of the sample passes through the gap between the back surface of the sample and the deposit suppressing member facing the sample, and passes through the sample stage. Characterized by being discharged from the plasma processing apparatus into the plasma processing apparatus. 6. The plasma processing apparatus according to claim 1, further comprising an electrostatic suction means for supporting said sample on said support. 7. The plasma processing apparatus according to claim 6, wherein said deposit suppressing member is held on said sample stage by electrostatic attraction means. 8. The plasma processing apparatus according to claim 7, wherein the temperature of the sample is controlled by the heat transfer gas introduced to the back surface of the sample, and a gap between the back surface of the sample and the deposit suppressing member is reduced to zero. .3 mm or less, and the temperature controllability of the outer peripheral portion of the sample is improved by the heat transfer effect of the heat transfer gas leaking into the gap. 9. A plasma processing apparatus having a vacuum processing chamber, a sample stage on which a sample to be processed in the vacuum processing chamber is mounted, plasma generating means, and gas supplying means for generating plasma. A plasma processing method, wherein the sample stage has a substantially flat surface supporting the sample and a concave outer peripheral surface recessed from the sample support surface around the sample stage, wherein the sample stage is in contact with the sample back surface. A step of arranging an annular sediment suppressing member adjacent to the outer periphery of the sample support surface on the outer peripheral surface of the sample stage and generating the plasma; a step of supporting the sample on the sample stage; and generating the plasma. Applying a high-frequency bias to the sample independently of the means to perform plasma processing; and deposits generated by the plasma processing passing through a gap between the back surface of the sample and the deposit suppressing member and surrounding the sample support surface. To reach the part The plasma processing method of the phenomenon suppressing process that, characterized in that it consists of. 10. The plasma processing method according to claim 9, wherein the method of supporting the sample on the sample stage is an electrostatic adsorption method. 11. The plasma processing method according to claim 9 or 10, wherein said deposit suppressing member is replaced with another clean deposit suppressing member of the same specification when cleaning the plasma processing chamber by opening to the atmosphere. A plasma processing method comprising a step. 12. The plasma processing method according to claim 9, wherein the plasma processing is activated through a gap between a concave outer peripheral portion of the sample support surface and a side wall of the sample support surface. Installing an active species consuming member that consumes a seed, and installing a deposit suppressing member having a surface smaller than the sample diameter in the gap between the active species consuming member and the sample support surface; Wherein the gap between the back surface of the sample and the opposing surface of the deposit suppressing member is 0.5 mm or less, preferably 0.3 mm or less. 13. The plasma processing method according to claim 12, wherein said plasma processing method is a silicon oxide film etching or a dielectric film etching, said etching gas contains fluorine, and said active species consuming member is made of silicon or silicon. A plasma processing method comprising a material containing carbon as a constituent element.