JP2006066824A - Plasma etching equipment and base, and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an equipment and a base which are composed of a structure capable of resolving a problem that the deflection of a wafer to the reaction chamber side of a vacuum atmosphere increases because of the thin thickness of wafer, and the surface temperature of the wafer exhibits uniformity when using a mechanical cramp and wafer-cooling helium gas on the base in a plasma etching equipment. <P>SOLUTION: A fine convex step is located near the outside circumference of the base, a space where a good heat transfer can be carried out between a platen and a substrate to some extent is held, and many gas vent holes of a small diameter are located near the outside circumference of the base when introducing a helium gas as a heating medium. The helium gas flows uniformly through the gas vent holes in a rated flow, and the gas pressure of back of the wafer is inclined to required extent between the center portion and the out side circumference to adapt to the deflection of the wafer. Consequently, the distribution of the temperature on the wafer surface can be uniformly kept, and the excessive deflection of the wafer and the non-uniformity of temperature on the wafer surface can be prevented by controlling the incline of gas pressure of the back of the wafer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a plasma etching apparatus provided with a base using a mechanical clamp, and a wafer whose rigidity is lowered by actively flowing a helium gas of a heat medium introduced between the wafer and the base. The present invention relates to a plasma etching apparatus, a base, and a driving method thereof for preventing the wafer from bulging out to the reaction chamber side and improving the cooling ability to make the in-plane temperature of the wafer uniform.

  For manufacturing semiconductor devices using wafers such as silicon, glass and GaAs, and for manufacturing various devices using a micro-electro-mechanical system (hereinafter referred to as MEMS), the wafer material itself or the material thereof is used. Etching is indispensable for etching the oxide film provided on the surface into a required shape, and dry etching using plasma is widely used.

  In the plasma etching method, low-pressure process gas plasma is generated in a reduced-pressure atmosphere, and, for example, silicon is etched by the generated plasma. As an example of the apparatus configuration, an inductively coupled plasma apparatus (referred to as Inductively Coupled Plasma, ICP) that can individually control plasma generation and plasma attraction is known.

  In this ICP apparatus, an alternating voltage is applied to the coil to generate plasma, an alternating voltage is applied to the substrate electrode on which the wafer is placed, and the plasma generated outside the reaction chamber is drawn into the reaction chamber, Etch the wafer.

  The base for placing the wafer in the reaction chamber is a place where the wafer is placed and fixed by means such as electrostatic adsorption or mechanical clamp, and the base itself is cooled or a heat transfer medium between the base and the wafer. The in-plane temperature of the wafer is uniformly maintained by filling the helium gas.

  In a conventional plasma etching apparatus employing a mechanical clamp, a plurality of radial and circumferential cooling gas dispersion grooves are formed on the surface of the base attachment serving as an electrode, and the cooling He gas is supplied to the base platen. It is configured to be supplied to the groove through a cooling gas supply pipe disposed so as to pass through. However, in such an apparatus, in the case of a compound semiconductor substrate such as GaAs, there is a problem that the etching depth varies, and this is because the electric field distribution on the base attachment is uneven due to the groove.

Therefore, as disclosed in Patent Document 2, for the purpose of improving the in-plane uniformity of the etching depth of the dielectric film on the wafer compound semiconductor wafer to be processed and mounted, as shown in FIG. The surface of 13b is made flat without a groove, and a space portion 16 is provided between the wafer 17 and the base attachment 13b. A heat medium helium gas is introduced into the space, and the helium gas is supplied to the base attachment 13b. The sealing member 18 is sealed so as not to leak into the reaction chamber 12 in a vacuum atmosphere by an O-ring 19 which is arranged around the clamp member 18.
JP 2003-77892 A JP 2003-133286 A JP 2004-119448 A

In the base of Patent Document 2 shown in FIG. 6, if the temperature difference occurs on the surface of the wafer 17 placed on the base attachment 13b, the etching processing amount may vary. In particular, when the dielectric film such as SiN film or SiO ₂ film formed on the semiconductor substrate is etched, the above-mentioned variation is remarkable.

  On the other hand, a glass wafer or a silicon wafer having a thin thickness and a reinforcing backing material cannot be electrostatically attracted when placed on a base. In addition, since a silicon wafer or the like that has a large amount of etching processing and has a thickness that becomes extremely thin after processing may be broken at the time of separation after processing by electrostatic attraction, the outer peripheral portion of the wafer is mechanically clamped.

  As described above, the etching apparatus having the base 13 having the above-described configuration shown in FIG. 5 has a relatively low vacuum atmosphere in a reaction chamber in which the rigidity of the substrate decreases with the progress of the etching process depending on the wafer type and processing pattern. The convex deflection amount of the wafer 17 due to the helium gas pressure increases to the side, and the distance between the central portion of the wafer 17 and the base attachment 13b may become too large.

  In this case, heat transfer between the central portion of the wafer 17 and the base attachment 13b is not sufficient, and the temperature distribution of the wafer deteriorates. For example, a temperature difference of 40 ° C. or more is generated between the central portion and the outer peripheral side of the wafer. It will adversely affect process performance.

  In the plasma etching apparatus, when a mechanical clamp and a wafer cooling helium gas are used as a base, the wafer is thin and the substrate rigidity is relatively lowered as the process proceeds. An object of the present invention is to provide an apparatus, a base and a driving method for the apparatus and the base, which can solve the problem that the deflection of the wafer to the chamber side increases and the in-plane temperature of the wafer is not uniform.

  In order to achieve uniform temperature in the surface of a wafer to be placed on a base using a mechanical clamp, the inventors provide, for example, a minute convex step near the base outer periphery, As a result of various studies on the method of introducing the helium gas as the heat medium while ensuring a gap in the range where good heat transfer is possible, a number of small-diameter vent holes are provided near the outer periphery of the base, and helium gas is passed through the vent holes. Is uniformly flown at a constant flow rate, so that the helium gas pressure on the backside of the wafer has a required slope between the center and the outer periphery to match the deflection of the wafer, thereby making the temperature distribution in the wafer surface uniform. It was found that it can be maintained.

  Further, the inventors arrange a ring of a porous material such as a metal near the outer periphery of the base with which the mechanical clamp of the wafer contacts to constitute an exhaust system to control the gas pressure in the gas introduction space within a predetermined range. At the same time, the inventors have found that controlling the inclination of the helium gas pressure on the backside of the wafer can prevent excessive deflection of the wafer and in-plane temperature non-uniformity, thereby completing the present invention.

  That is, the present invention is a base to which a voltage can be applied, has a clamping means for placing a wafer and mechanically fixing the outer periphery thereof, and has a concave portion or a similar shape to the wafer on the upper surface of the base. One cooling gas introduction space is formed on the back side of the wafer mounted with one ring-shaped convex portion, or a concave portion and a ring-shaped concave portion similar to the wafer or a plurality of ring-shaped convex portions on the upper surface of the base. Two or more cooling gas introduction spaces are formed on the back surface side of the wafer placed and placed, and the cooling gas supply passage is arranged to move through the cooling gas introduction space while the cooling gas is in contact with the back surface of the wafer. A plasma etching apparatus base comprising a cooling gas exhaust hole path.

  The present invention also provides a mounting base for a substrate to be processed, a power supply means for applying high-frequency power to the base, a processing gas supply means for supplying a processing gas in a room with a flow rate and a pressure adjusted, and its It has a processing chamber provided with an evacuation means, and a plasma generating means for applying a high frequency power independently of the base and converting the processing gas into plasma, and the base has the above-described configuration. Is a plasma etching apparatus.

  Furthermore, the present invention is characterized in that, in the plasma etching apparatus having the above configuration, the cooling gas is introduced into the cooling gas introduction space at a predetermined flow rate, and the cooling gas is controlled so that the pressure in the introduction space becomes constant. This is a method for driving a plasma etching apparatus.

  According to the present invention, the cooling gas introduction space is formed on the back surface side of the wafer on the upper surface of the base of the plasma etching apparatus, and the helium gas is allowed to flow uniformly at a constant flow rate. By adjusting so that more heat transfer is performed in the central part where the deflection of the wafer increases, the temperature distribution of the wafer is improved and the etching process performance is improved. It is done.

  According to the present invention, the temperature distribution in the wafer surface is reduced with respect to wafers that require mechanical clamping, such as wafers that cannot be electrostatically attracted when placed on a base, or silicon wafers that become extremely thin after processing. Plasma etching can be performed without causing variations, and the amount of processing in any part of the wafer surface is equal, and high-quality processing can be provided.

  The plasma etching apparatus base 1 according to the present invention forms a cooling gas introduction space 3 between the back surface of the wafer 17 placed on the upper surface of the base 1 as shown in FIG. A cooling gas supply path 4 and an exhaust path 5 are provided so as to move in the cooling gas introduction space while being in contact with each other. In the case where the base is composed of the base attachment shown in the example of FIG. 6 and the base platen that holds the base attachment, the cooling gas supply system path 4 and the exhaust system path 5 are provided on both, but the attachment and the platen The same applies to a base constructed integrally with each other, and FIGS. 1 to 4 exemplify attachments and are simply referred to as a base 1.

  The cooling gas introduction space 3 is formed by providing a concave portion or a ring-shaped convex portion similar to the wafer 17 on the upper surface of the base 1, but the example shown in FIG. A recess having a depth of several tens of μm is formed. A lip seal 2 is arranged on the end circumferential portion 1 a on the upper surface of the base 1 and has a function of sealing between the outer peripheral portion of the wafer 17 pressed by the clamp member 18 and the cooling gas introduction space 3. Yes.

  Here, one cooling gas supply hole 4 is provided in the center of the upper surface of the base 1, and a plurality of cooling gas exhaust holes 5 are provided in the vicinity of the clamp member 18 on the upper surface of the base 1. A valve 6 for controlling the pressure in the cooling gas introduction space 3 is arranged in the cooling gas exhaust passage 5. Accordingly, the introduced cooling gas flows evenly from the center of the base 1 toward the outer periphery of the base 1. Note that a plurality of cooling gas supply holes 4 may be arranged at the center of the upper surface of the base 1.

  The cooling gas introduction space 3 can also be formed by providing a ring-shaped convex portion such as an O-ring having an outer peripheral shape similar to that of the wafer 17 on the upper surface of the base 1 and having different diameters. It is possible to arrange two or three ring-shaped convex portions concentrically, and two to three cooling gas introduction spaces 3 are formed.

  The cooling gas introduction space 3 shown in FIG. 2 is a cooling gas introduction space 3 in which a porous material 7 is disposed in the vicinity of the clamp member 18 at an end circumferential portion 1a on the upper surface of the base 1 in which a concave portion similar to the wafer 17 is formed. The cooling gas exhaust passage 5 is connected to the porous material 7. The cooling gas introduced from the cooling gas supply hole 4 at the center of the upper surface of the base 1 (not shown) flows evenly toward the ring-shaped porous material 7 arranged on the outer peripheral side of the base 1. When such a porous material 7 is used, there is an effect that the cooling gas flows more evenly than the cooling gas exhaust passage 5 alone.

  The entire ring-shaped porous material 7 is made of a porous material to form a cooling gas exhaust passage. However, a part of a required portion of the porous material 7 can be made of a porous material, and an exhaust port is also required. It can be arranged at multiple locations at intervals.

  The cooling gas introduction space 3 shown in FIG. 3 is the same as the configuration of FIG. 1, and a plurality of cooling gas supply holes 4 in the center of the upper surface of the base 1 and a plurality of clamp members 18 in the vicinity of the upper surface of the base 1. Although the cooling gas exhaust passage 5a is provided, the exhaust gas 8 and the cooling gas made of a plurality of porous materials are provided at predetermined intervals in the circumferential direction at an intermediate position between the cooling gas supply passage 4 and the cooling gas exhaust passage 5a. An exhaust hole 9 is provided. Therefore, the cooling gas introduced from the center of the upper surface of the base 1 can be sucked and exhausted from the exhaust hole 8 made of a porous material.

  In the configuration of FIG. 3, the cooling gas exhaust hole 5a on the outer peripheral side is changed to a gas supply hole, so that the cooling gas supply hole 4 in the center of the cooling gas introduction space 3 and diverted cooling at a plurality of positions on the outer peripheral side are performed. It is also possible to adopt a configuration in which the cooling gas introduced from the gas supply hole passage is sucked and exhausted from the exhaust hole 8 made of a porous material to control the flow rate and pressure.

  Further, in the configuration of FIG. 1, the introduction system and the exhaust system are interchanged, and the center of the upper surface of the base is used as the cooling gas exhaust hole, and the ring-shaped porous sealing material on the outer peripheral side of the upper surface of the base is used as the cooling gas introduction hole. As described above, the cooling gas can be introduced from the outer periphery of the base 1 and can flow to the center of the base 1.

  The configuration of FIG. 4 is basically the same as the configuration of FIG. 1, but a ring-shaped ridge 1b is provided between the cooling gas supply passage 4 at the center of the upper surface of the base 1 and the end circumferential portion 1a. This is a configuration in which two chambers, a circular cooling gas introduction space 3a and a ring-shaped cooling gas introduction space 3b, are provided. Cooling gas exhaust holes 5b are arranged at predetermined intervals on the inner peripheral side of the ring-shaped ridge 1b, and a plurality of cooling gas exhaust holes are provided at the outer periphery of the cooling gas introduction space 3a from the cooling gas supply hole 4 at the center. The air is exhausted from the passage 5b by controlling the flow rate and pressure. Also in the case of the ring-shaped cooling gas introduction space 3b, the cooling gas supply holes 4b are arranged at predetermined intervals on the outer peripheral side of the ring-shaped protrusion 1b, and are sucked from the cooling gas exhaust hole 5 on the outer peripheral side of the base 1. By exhausting and controlling the flow rate and pressure, a predetermined amount of cooling gas can be introduced and flowed down.

  The ring-shaped ridge 1b can be selected as appropriate for the width of the ridge, and is particularly narrow and lacks contact with the back surface of the wafer 17, causing leakage between the two chambers of the circular and ring-shaped cooling gas introduction spaces 3a and 3b. However, the function of the cooling gas to the wafer 17 is not impaired.

  In this invention, as the porous material, any of known metals, alloys, ceramics, and resins can be used. Specifically, sintered bodies of various materials such as aluminum, stainless steel, titanium, zirconia, and various ceramics. And a porous body of polytetrafluoroethylene. Moreover, a porous body by thermal spraying such as aluminum can be used.

  In the present invention, the O-ring and the lip seal can be appropriately selected from many known materials such as fluorine rubber, perfluoroelastomer, silicone rubber, and fluorosilicone rubber.

  FIG. 5 is an explanatory diagram of a configuration of an inductively coupled plasma (ICP) apparatus for carrying out a wafer etching method according to an embodiment of the present invention. The etching apparatus shown in FIG. 5 includes, as a processing chamber 10, an upper plasma generation chamber 11 that generates plasma, and a base 13 for plasma processing the wafer 17 to be etched by drawing the generated plasma. The lower reaction chamber 12 is provided.

  The exhaust system path 14 as the exhaust means in the processing chamber includes a passage member connected to the reaction chamber 12 and a vacuum pump connected to the passage member. The pressure in the processing chamber 10 is reduced to a required range and controlled by an open / close valve (not shown) having a control mechanism interposed between the vacuum pump, the reaction chamber 12 and the passage member.

For example, the gas supply system path 15 for supplying the etching SF ₆ gas, the oxidizing gas containing oxygen, and the protective film forming C 4 F 8 gas includes a path member connected to the upper part of the plasma generation chamber 11, and not shown. It consists of a flow control device and a gas cylinder corresponding to each gas. Various gases are fed into the plasma generation chamber 11 after the flow rate is adjusted by a flow rate control device from a gas cylinder.

  The plasma generating means includes a coil 20 disposed on the outer periphery of a plasma generating chamber 11 having a cylindrical shape made of ceramic, and a high-frequency power source 22 connected to the coil 20 via a matching unit 21. When the plasma etching apparatus is in operation, AC power having a frequency of 13.56 MHz is applied to the coil 20, and the gas supplied to the processing chamber is turned into plasma.

  A base 13 on which the wafer 17 is placed is accommodated in the reaction chamber 12. In order to actively draw the plasma generated by applying high-frequency power to the coil 20 to the wafer 17, A high frequency power supply 24 having a frequency of 13.56 MHz is connected to the coil 20 via a matching unit 23 separately from the coil 20.

  A control device (not shown) has functions of reactive gas flow rate control, base power control, and coil power control, and controls the gas flow rate control device described above to supply etching gas, oxidizing gas, and protective film forming gas from the gas cylinder. The high frequency power supply 22 and the matching unit 21 are applied to the above-described base 13 by controlling the high frequency power supply 22 and the matching unit 21, and the high frequency power supply 24 and the matching unit 23 are applied to the coil 20. Control and apply high frequency power.

  In particular, the reactive gas flow rate control includes an etching process in which etching is performed by supplying only an etching gas for a predetermined time, a process in which only an oxidizing gas is supplied for a predetermined time, and a protective film is formed by supplying only a protective film forming gas for a predetermined time. The step of depositing the protective film to be formed can be sequentially repeated.

  In the etching apparatus of the present invention, an attachment having the same structure as the structure shown in FIGS. 1 to 4 described above is adopted for the base composed of the attachment and the platen, and the cooling gas supply passage or the cooling gas exhaust passage or the same is adopted. Both are provided with a means for adjusting the gas pressure and / or gas flow rate for controlling the pressure and flow rate in the cooling gas introduction space to be constant.

  Here, in order to introduce the cooling gas into the cooling gas introduction space at a predetermined flow rate and control the cooling gas so that the pressure in the introduction space becomes constant, a capacitance vacuum gauge and a mass flow controller are installed in the cooling gas introduction space. Then, the cooling gas introduction flow rate may be controlled by a mass flow controller so that the pressure becomes constant.

  The pressure in the central part of the cooling gas introduction space is controlled based on the pressure. Basically, the pressure in the central part is controlled by the introduction pressure, and the outer peripheral part pressure is determined by the shape and size of the exhaust hole and the gas permeability of the porous material. When suction exhaust is used, the pressure is controlled in the same manner as the introduction unit.

Comparative Example In an etching apparatus provided with a base for a plasma etching apparatus having a conventional configuration shown in FIG. 6, an 8 inch outer diameter silicon wafer was used, a thermo label was attached thereto, and the wafer was mounted on the upper surface of the base during the etching process. The center part of the placed wafer and the temperature inside the clamp member at the outer peripheral part were measured. As a result, the central portion was 88 to 92 ° C, the outer peripheral portion was 49 to 53 ° C, and the temperature difference was 35 to 43 ° C.

The plasma conditions for measuring the wafer surface temperature were as follows.
Gas type: SF ₆
Coil power (plasma excitation power): 2000W
Platen power (substrate power ← for plasma pulling): 15W
Gas flow: 300sccm
Chamber pressure: 5Pa

EXAMPLE In the plasma etching apparatus of the present invention shown in FIG. 5 equipped with the base attachment of FIG. 1, an 8-inch outer diameter silicon wafer was placed on the upper surface of the base attachment during the etching process as in the comparative example. The temperature inside the center portion of the wafer and the inside of the outer peripheral clamp member were measured. As a result, the central portion was 88 to 92 ° C, the outer peripheral portion was 82 to 87 ° C, and the temperature difference was 1 to 10 ° C.

  In the etching apparatus of the comparative example, the difference in the temperature distribution of the wafer was 35 to 43 ° C., but in the embodiment of the present invention, it is clear that it is greatly reduced to 1 to 10 ° C. It can be seen that etching process performance with good uniformity can be obtained.

  This invention enables plasma etching without causing variations in the temperature distribution in the wafer surface for wafers that require mechanical clamping, such as wafers made of materials that cannot be electrostatically attracted, and silicon wafers that become extremely thin after processing. It can be processed, and the processing amount at any point in the wafer surface is equivalent, can provide high-quality processing, and is optimal for manufacturing various devices by MEMS.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal explanatory view showing a configuration of a main part of a base for a plasma etching apparatus according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal explanatory view showing a configuration of a main part of a base for a plasma etching apparatus according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal explanatory view showing a configuration of a main part of a base for a plasma etching apparatus according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal explanatory view showing a configuration of a main part of a base for a plasma etching apparatus according to the present invention. It is explanatory drawing which shows the structural example of the plasma etching apparatus by this invention. It is explanatory drawing which shows the structural example of the conventional plasma etching apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Lip seal 3, 3a, 3b Cooling gas introduction space 4, 4a, 4b Cooling gas supply passage 5, 5a, 5b, 9 Cooling gas exhaust passage 6 Valve 7 Porous material 8 Exhaust hole 10 Processing chamber 11 Plasma generation chamber 12 Reaction chamber 13 Base 14 Exhaust system path 15 Reaction gas supply system path 16 Space part 17 Wafer 18 Clamp member 19 O-ring 20 Coil 21, 23 Matching unit 22, 24 High frequency power supply

Claims (12)

A base to which a voltage can be applied, has a clamping means for placing the wafer and mechanically fixing the outer periphery thereof, and has one concave portion or one ring-shaped convex portion similar to the wafer on the upper surface of the base A cooling gas inlet space and a cooling gas exhaust hole are formed so that one cooling gas introduction space is formed on the back surface side of the wafer placed and mounted, and the cooling gas introduction space is moved while the cooling gas is in contact with the back surface of the wafer. A base for plasma etching equipment with a path. It is a base to which voltage can be applied and has clamping means for placing the wafer and mechanically fixing the outer periphery of the wafer. On the upper surface of the base, a concave part and ring-shaped concave part or multiple ring-like parts similar to the wafer A plurality of cooling gas introduction spaces are formed on the back surface side of the wafer placed with the convex portions, and the cooling gas supply passage and the cooling gas are moved so that the cooling gas introduction space moves while contacting the cooling gas on the back surface of the wafer. A base for a plasma etching apparatus provided with an exhaust hole path. At least one cooling gas supply hole is formed in the center or inner peripheral surface of the cooling gas introduction space, and a plurality of cooling gas exhaust holes are formed on the outer surface of the introduction space or in the vicinity of the clamping means. The base for a plasma etching apparatus according to claim 1 or 2 provided. A plurality of cooling gas exhaust holes are provided in the center or inner peripheral surface of the cooling gas introduction space, and a plurality of cooling gas supply holes are provided on the outer peripheral side of the introduction space or in the vicinity of the clamping means. The base for a plasma etching apparatus according to claim 1 or claim 2. The base for a plasma etching apparatus according to claim 1 or 2, wherein the cooling gas introduction hole, the cooling gas exhaust hole, or both are made of a porous material. The base for a plasma etching apparatus according to claim 1 or 2, wherein a part or all of the ring-shaped convex portion is made of a porous material to form a cooling gas exhaust passage. The base for a plasma etching apparatus according to claim 6, wherein the porous material is any one of a metal, an alloy, a ceramic, and a resin. A processing base comprising: a mounting base for a substrate to be processed; power supply means for applying high-frequency power to the base; processing gas supply means for supplying a processing gas by adjusting the flow rate and pressure; A chamber and plasma generating means for applying a high-frequency power independently of the base and converting the processing gas into plasma. The base mounts a wafer and mechanically fixes the outer periphery thereof. And a cooling gas introduction space is formed on the rear surface side of the wafer placed by providing one concave portion or one ring-shaped convex portion similar to the wafer on the upper surface of the base. A plasma etching apparatus having a configuration in which a cooling gas supply hole path and a cooling gas exhaust hole path are provided so as to move in the cooling gas introduction space while contacting the cooling gas. A processing base comprising: a mounting base for a substrate to be processed; power supply means for applying high-frequency power to the base; processing gas supply means for supplying a processing gas by adjusting the flow rate and pressure; A chamber and plasma generating means for applying a high-frequency power independently to the base and converting the processing gas into a plasma, and a recess similar to the wafer and a ring-shaped recess or a plurality of ring-shaped recesses on the upper surface of the base A plurality of cooling gas introduction spaces are formed on the back surface side of the wafer placed with the convex portions, and the cooling gas supply passage and the cooling gas are moved so that the cooling gas introduction space moves while contacting the cooling gas on the back surface of the wafer. A plasma etching apparatus having a configuration in which an exhaust hole path is provided. 10. The plasma etching apparatus according to claim 8 or 9, wherein a gas pressure or a gas flow rate for controlling the pressure in the cooling gas introduction space to be constant in the cooling gas supply hole path and / or the cooling gas exhaust hole path. Or the plasma etching apparatus provided with the adjustment means of both of them. The plasma etching apparatus according to claim 8 or 9, wherein a cooling gas is introduced into the cooling gas introduction space at a predetermined flow rate, and the cooling gas is controlled so that the pressure in the introduction space becomes constant. Driving method. The method for driving a plasma etching apparatus according to claim 11, wherein the control is performed based on a pressure in a central portion of the cooling gas introduction space.

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