JP5190203B2 - Plasma generator, plasma processing apparatus, and plasma processing method - Google Patents

Description

  The present invention relates to a plasma generation apparatus, a plasma processing apparatus, and a plasma processing method, and more particularly to a plasma generation apparatus using a microwave, a plasma processing apparatus such as an etching apparatus equipped with the plasma, and a plasma processing method.

  The dry process using plasma is used in a wide range of technical fields such as semiconductor manufacturing equipment, surface hardening of metal parts, surface activation of plastic parts, and non-chemical sterilization. For example, when manufacturing a semiconductor device or a liquid crystal display, various plasma treatments such as ashing, dry etching, thin film deposition, or surface modification are used. The dry process using plasma is advantageous in that it is low-cost, high-speed, and can reduce environmental pollution because it does not use chemicals.

  As a typical apparatus for performing such plasma processing, there is a “microwave excitation type” plasma processing apparatus that excites plasma with microwaves having a wavelength of several hundred MHz to several tens GHz. Microwave-excited plasma sources are widely used for resist ashing without damage and anisotropic etching with a bias voltage applied because the plasma potential is lower than that of high-frequency plasma sources. .

  Here, a member made of high-purity quartz is used for a portion where microwaves are introduced to excite plasma. However, the surface of the member is etched and consumed under conditions of high plasma density and high temperature. Therefore, a technique has been proposed in which a material having high plasma resistance is attached to a portion consumed by etching (see Patent Document 1).

However, in the technique disclosed in Patent Document 1, a gap for mounting (insertion) is generated between the outer quartz tube inner diameter and the inner ceramic inner tube outer diameter. For this reason, plasma is also generated in this gap, and the inside of the quartz tube may be etched. Further, since the ceramic inner tube is provided in the decompression space, there is a problem in terms of cooling because it is difficult to dissipate heat. In addition, particles may be generated due to rubbing when mounting (inserting) the ceramic inner tube, or rubbing due to a difference in thermal expansion coefficient between the outer quartz tube and the inner ceramic inner tube. there were.
Japanese Patent No. 2978991

  The present invention provides a plasma generating apparatus, a plasma processing apparatus, and a plasma processing method capable of generating a plasma over a wide range with a long lifetime of a member to which a microwave is introduced.

According to one aspect of the present invention, a dielectric that partitions the decompressed space and the atmospheric pressure space, and a microwave waveguide are provided, and the dielectric is inserted into the dielectric from the atmospheric pressure space via the microwave waveguide. A plasma generator for introducing a microwave to generate plasma on the decompressed space side,
A plasma expansion member provided on the atmospheric pressure space side of the dielectric and having a dielectric constant lower than that of the dielectric is further provided, and the microwave is introduced into the dielectric via the plasma expansion member The plasma expansion member has an inner peripheral surface and an outer peripheral surface exposed to an atmospheric pressure space, and a gap is provided between the dielectric and the inner peripheral surface of the plasma expansion member. the plasma generating apparatus characterized by clearance is open to the atmosphere is provided.

  According to another aspect of the present invention, there is provided a plasma processing apparatus comprising the above-described plasma generation apparatus, wherein plasma processing of an object to be processed can be performed using the generated plasma. The

  Furthermore, according to another aspect of the present invention, there is provided a plasma processing method characterized in that plasma processing is performed on an object to be processed by the generated plasma using the plasma generator. .

  ADVANTAGE OF THE INVENTION According to this invention, the lifetime of the member of the part which introduce | transduces a microwave is long, and the plasma generator, plasma processing apparatus, and plasma processing method which can generate | occur | produce a plasma in a wide range are provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining a plasma generator 1 according to an embodiment of the present invention. 1A is a schematic cross-sectional view of the front side of the plasma generator 1, and FIG. 1B is a schematic cross-sectional view taken along the AA direction of FIG. 1A.
A plasma generator 1 shown in FIG. 1 is used in a microwave plasma processing apparatus generally called a “CDE (Chemical Dry Etching) apparatus”, and includes a discharge tube 2 that is a dielectric, and a plasma expansion member 3. , An introduction waveguide 4 and a cooling means 5 are provided.

Here, CF ₄ (tetrafluorocarbon) gas, which is less deposited and has stable etching characteristics, has been widely used for etching semiconductor wafers as a fluorine-based etching gas. However, CF ₄ gas is a kind of PFC (perfluorocarbon) gas and has a high global warming potential and is not preferable for the global environment. Therefore, it is necessary to suppress its use as much as possible. Therefore, NF ₃ (nitrogen trifluoride) gas, which has a lower warming coefficient than CF ₄ gas and easily obtains a high etching rate, has come to be used.

However, since NF ₃ gas has high decomposability and easily absorbs the microwave M, the generation range of the plasma P tends to be narrow and concentrated. When the plasma P is generated in a concentrated manner, a place where the temperature is locally high is generated on the inner surface of the discharge tube 2 and the temperature distribution becomes large, so that a high thermal stress may be generated and the discharge tube 2 may be damaged. In addition, since the chemical etching rate increases at a high temperature, local wear may occur, which may cause contamination and foreign matter. In addition, a material having high fluorine plasma resistance (for example, alumina (Al ₂ O ₃ ), sapphire, boron nitride (BN), aluminum nitride, yttrium aluminum garnet (YAG; Yttrium Aluminum Garnet) generally has a high dielectric constant and is difficult to propagate the microwave M. This also causes the plasma P to be generated intensively.

  In order to suppress the intensive generation of the plasma P and extend the generation range of the plasma P to improve the temperature distribution, an additive gas (for example, argon gas) is added, or the plasma P is controlled by a magnetic field. It is possible to do. However, the additive gas may affect the etching rate and the like, and it cannot be generally said that it can be used. Further, the control of the plasma P by the magnetic field causes a new problem that the apparatus becomes large and complicated.

As a result of the study, the present inventor has provided a member (plasma expansion member 3) having a dielectric constant lower than that of the discharge tube 2 on the outer peripheral surface of the discharge tube 2 when the microwave M is introduced into the discharge tube 2. Since the propagation range of the wave M can be expanded and the generation range of the plasma P can be expanded, it has been found that the intensive generation of the plasma P can be suppressed.
This is not necessarily clear, but is considered to be due to the following. In general, microwaves are less likely to propagate as the dielectric constant increases. Therefore, if the microwave is directly introduced into the discharge tube 2 having a high dielectric constant, the microwave is not propagated in the axial direction of the discharge tube 2 and concentrated in the portion immediately below the introduced portion. Radiation occurs and a plasma is generated in a concentrated manner. On the other hand, if a member (plasma expansion member 3) having a dielectric constant lower than that of the discharge tube 2 is provided and microwaves are introduced thereto, the dielectric constant is higher in the microwave radiation direction (microwaves). Since there is the discharge tube 2, most of the introduced microwave is not radiated as it is, but propagates as a surface wave on the interface between the plasma expansion member 3 and the discharge tube 2, Thereafter, it is considered that the light is emitted toward the discharge tube 2. For this reason, the generation range of the plasma P is expanded, and the intensive generation of the plasma P is suppressed.
A material having a lower dielectric constant than the discharge tube 2 may be used for the plasma expansion member 3.
Here, the discharge tube 2 is made of a dielectric material, for example, quartz (SiO ₂ ), alumina (Al ₂ O ₃ ), sapphire, boron nitride (BN), aluminum nitride, yttrium aluminum garnet (YAG; Yttrium Aluminum). Garnet) can be used. However, considering the consumption of the discharge tube 2 due to highly reactive fluorine plasma, alumina (Al ₂ O ₃ ), sapphire, boron nitride (BN), aluminum nitride, yttrium oxide, aluminum, garnet, which have high fluorine resistance. It is preferable to use (YAG; Yttrium Aluminum Garnet).

Therefore, for example, quartz (SiO ₂ ) having a relative dielectric constant of about 4 may be used as the plasma expansion member 3, and alumina (Al ₂ O ₃ ) having a relative dielectric constant of about 8 may be used as the discharge tube 2. . However, the present invention is not limited to the above-described materials and combinations thereof, and can be appropriately changed.

Next, returning to FIG. 1, the configuration of the plasma generator 1 will be described.
The discharge tube 2 and the plasma expansion member 3 are inserted through the introduction waveguide 4 so as to be substantially orthogonal. The introduction waveguide 4 is provided with an annular slot 4 a for radiating the microwave M propagating from the direction orthogonal to the axial direction of the plasma expansion member 3 toward the plasma expansion member 3. The plasma expansion member 3 may be inserted so that the positions of the end surfaces 3a and 3b thereof are substantially symmetrical with respect to the slot 4a of the introduction waveguide 4 as a reference. You can also

  As shown in FIG. 1B, in a portion where the discharge tube 2 and the plasma expansion member 3 are inserted through the introduction waveguide 4, a direction perpendicular to the axial direction of the plasma expansion member 3 and the microwave M The inner dimension of the introduction waveguide 4 in the direction orthogonal to the traveling direction, that is, the dimension of the passage width W of the pair of microwave paths provided inside the introduction waveguide 4 is set to a half wavelength (λ / 2) and a value smaller than one wavelength (λ) of the microwave M is preferable. If the dimension of the passage width W is set to such a value, the propagated microwave M is not affected by the plasma P in the discharge tube 2 and goes around to the back side of the discharge tube 2 in the same mode. Can do. Therefore, generation of plasma P can be stabilized. That is, by making the passage width W larger than the half wavelength (λ / 2) of the microwave M, the microwave M can be propagated, and the passage width W is made smaller than one wavelength (λ) of the microwave M. Thus, the generation of multimode electromagnetic field distribution can be prevented. Incidentally, when the wavelength (λ) in the introduction waveguide of the microwave M of 2.45 GHz is 160 mm, the passage width W is preferably 80 mm <passage width W <160 mm.

The inside of the discharge tube 2 is a plasma generation chamber C for generating plasma P, but a portion facing the slit 4a is a substantially central region of the plasma generation chamber C.
The plasma expansion member 3 is substantially coaxial with the discharge tube 2. At this time, the inner peripheral surface of the plasma expansion member 3 and the outer peripheral surface of the discharge tube 2 may be in contact with each other, but it is preferable to provide the gap G1 in consideration of the effect of expanding the plasma generation range described above. This is because the gap G1 is filled with air having a relative dielectric constant of 1, and thus has an effect of reducing the apparent relative dielectric constant of the plasma expansion member 3. In this case, it is preferable to provide a spacer (not shown) made of silicon rubber or the like on the outer peripheral surface of the discharge tube 2 so as to make the size of the gap G1 uniform.

In addition, the size of the gap G1 is preferably large in consideration of the effect of expanding the plasma generation range described above. However, if the size is too large, the cooling effect of the cooling means 5 to be described later may be adversely affected due to heat insulation of air. is there. As a result of experiments, it was found that the gap G1 is particularly preferably 0.5 mm to 2.0 mm. It is confirmed that when the gap G1 exceeds 2.0 mm, the discharge in the discharge tube 2 becomes unstable, and the discharge tube 2 and the plasma expansion member 3 are connected to the cylinder as in the present embodiment. In the case of manufacturing with a mold, if an attempt is made to secure a gap of 0.5 mm or less as the gap G1, the concentricity is required with high accuracy and the cost becomes high.
The cooling block 6 of the cooling means 5 is provided so as to surround the outer peripheral surface of the plasma expansion member 3 at and around the insertion portion between the plasma expansion member 3 and the introduction waveguide 4. Is cooled by circulating cooling water. A gap G2 (for example, about 1 mm) is formed between the plasma expansion member 3 and the plasma expansion member 3.

  The cooling block 6 is provided with a gas supply path 8 for supplying an inert gas such as nitrogen gas to the gap G2. The cross-sectional area of the gas supply path 8 is set so small that the microwave M does not leak. As the cooling effect is enhanced by the supplied inert gas, purge is performed and oxygen in the atmosphere is excluded, so that generation of ozone can be suppressed.

  In order to enhance the effect of absorbing the radiant heat from the plasma P, a conductor or a dielectric having a high radiant heat absorption rate may be provided inside the cooling block 6. In addition, painting the inner wall of the cooling block 6 in black is also effective in enhancing the effect of absorbing radiant heat.

If the cross-sectional dimension in the vicinity of the plasma expansion member 3 is exemplified, the outer diameter of the discharge tube 2 made of alumina (Al ₂ O ₃ ) is about 25.4 mm, the thickness is about 1 to 2 mm, quartz (SiO ₂ The outer diameter of the plasma expansion member 3 is about 38 mm, the thickness is about 5 to 7 mm, and the inner diameter of the cooling block 6 is about 40 mm. However, it is not necessarily limited to these dimensions, and can be changed as appropriate.

FIG. 2 is a schematic perspective view for explaining the appearance of the plasma generator 1.
FIG. 3 is a schematic cross-sectional view for explaining an axial cross-section of FIG.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and description is abbreviate | omitted.

  As shown in FIGS. 2 and 3, a gas introduction part 7 is connected to one end (left end in FIGS. 2 and 3) of the discharge tube 2 of the plasma generator 1, and the gas introduction part 7 is interposed in the discharge tube 2. Etching gas G is introduced. Further, a gas carrier 9 is connected to the other end (the right end in FIGS. 2 and 3) of the discharge tube 2 of the plasma generator 1, and mainly neutral active species among the plasma products are connected to the gas carrier 9. It is conveyed toward the chamber 14 (refer FIG. 4) mentioned later via this. The cooling block 6 of the cooling means 5 is provided with joints 10a and 10b. Cooling water is supplied from one joint 10a into the cooling block 6, and cooling water is discharged from the other joint 10b. Cooling water can be circulated. The cooling water is supplied by a cooling water supply means (not shown). Further, the drainage from the cooling block 6 can be reused through a filter, a cooler, or the like. Further, as described above, the introduction waveguide 4 in the portion through which the discharge tube 2 and the plasma expansion member 3 are inserted has a donut shape.

Next, the operation of the plasma generator 1 will be described.
First, the inside of the discharge tube 2 is depressurized to a predetermined pressure by a depressurizing means 11 (see FIG. 4) such as a dry pump. Next, a predetermined amount of etching gas G (for example, NF ₃ ) is introduced into the discharge tube 2 through the gas introduction unit 7 from the gas supply means 12 (see FIG. 4). On the other hand, a microwave M having a predetermined power is introduced into the plasma generation chamber C in the discharge tube 2 through the introduction waveguide 4 and the plasma expansion member 3 from the microwave generation means 13 (see FIG. 4). Further, cooling water is supplied into the cooling block 6 of the cooling means 5 to cool the plasma expansion member 3 and the discharge tube 2, and an inert gas such as nitrogen gas is supplied from the gas supply path 8 to cool it. And suppression of ozone generation.

  The microwave M that has propagated through the introduction waveguide 4 is first radiated to the plasma expansion member 3 from the annular slot 4a. The microwave M radiated to the plasma expansion member 3 is radiated toward the discharge tube 2 and introduced into the plasma generation chamber C. At this time, the propagation range of the microwave M can be expanded by the action of the plasma expansion member 3, and the generation range of the plasma P can also be expanded, so that the intensive generation of the plasma P can be suppressed. become.

  Plasma P is generated by the introduced microwave M, and the etching gas G is excited and activated to generate plasma products such as neutral active species and ions. The generated plasma product is transferred into the chamber 14 (see FIG. 4) via the gas transfer unit 9. At this time, ions having a short lifetime cannot reach the chamber 14, and only neutral active species having a long lifetime reach the chamber 14, and the object to be processed is etched.

  As described above, according to the plasma generator 1 according to the present embodiment, since the intensive generation of the plasma P can be suppressed, the discharge tube 2 is damaged due to thermal stress, and the discharge tube 2 is locally localized. Wear can be suppressed.

  Further, in order to extend the life of the discharge tube 2, the thickness of the tube may be increased. However, if the thickness is increased, a large temperature difference is generated between the inner surface and the outer surface of the tube, and the discharge tube 2 is caused by thermal stress. There is a risk of damage. Even in such a case, according to the plasma generator 1 according to the present embodiment, since the temperature distribution can be made uniform by suppressing the intensive generation of the plasma P, the temperature difference between the inner surface and the outer surface of the tube. Can be reduced. Therefore, even if the thickness of the discharge tube 2 is increased, there is little risk of damage due to thermal stress, and the life can be extended. Further, if the thickness of the tube is increased, the propagation range of the microwave M is expanded, so that the concentration of the plasma P can be further suppressed.

In addition, there is an advantage that a special additive gas or the like is not required to suppress the concentration of the plasma P, and the versatility is excellent, and a complicated and large apparatus is not required as in the control of the plasma P by a magnetic field.
In addition, when the gap G1 is provided, when the discharge tube 2 or the plasma expansion member 3 is replaced for maintenance or the like, the attachment and detachment can be easily performed, and the production efficiency can be improved.

  Further, when the discharge tube 2 or the plasma expansion member 3 is attached or detached, the inside of the discharge tube 2 is not rubbed, and the member is rubbed into the inside of the discharge tube 2 during maintenance as in the technique disclosed in Patent Document 1. There is no risk of particle generation.

  Even if the discharge tube 2 and the plasma expansion member 3 are expanded and contracted by starting and stopping the plasma generator 1, the discharge tube 2 and the plasma expansion member 3 rub against the outside of the discharge tube 2. There is no rubbing inside. Therefore, even if the plasma generator 1 is repeatedly started and stopped, unlike the technique disclosed in Patent Document 1, there is no possibility that particles due to friction of the members are generated inside the discharge tube 2.

Such generation of particles due to rubbing is a serious problem for a semiconductor device that requires fine processing, but according to the plasma generator 1 according to the present embodiment, such a problem does not occur. .
In addition, unlike the technique disclosed in Patent Document 1, since there is no member inside the discharge tube 2, there is no risk of abnormal discharge occurring between the discharge tube 2 and the internal member.

Moreover, even with a prone NF ₃ gas concentration of plasma P, can be relaxed concentration of plasma P, NF ₃ gas that warming potential than CF ₄ gas can also be increased etching rate lower You can fully enjoy the features of
Moreover, since the generation range of the plasma P can be expanded, the region where the plasma product is generated is expanded, and the generation efficiency of the plasma product can be increased.

Next, a CDE (Chemical Dry Etching) apparatus provided with the plasma generator 1 according to the present embodiment will be described.
FIG. 4 is a schematic cross-sectional view for explaining the CDE apparatus 100 including the plasma generation apparatus 1.
In addition, description of the plasma generator 1 demonstrated in FIG. 1 is abbreviate | omitted.
As shown in FIG. 4, the CDE apparatus 100 includes a plasma generator 1, a decompression unit 11, a gas supply unit 12, a microwave generation unit 13, a chamber 14, a control unit 15, and the like.

  The chamber 14 has a substantially cylindrical shape with a bottom, and an opening end thereof is closed with a top plate 14a. An electrostatic chuck 16 incorporating heating means such as a heater is provided inside the chamber 14, and a workpiece Wf (for example, a semiconductor wafer) can be placed and held on the upper surface thereof.

  A decompression means 11 such as a dry pump is connected to the bottom surface of the chamber 14 via a pressure controller (Auto Pressure Controller, APC) 17. The pressure controller 17 controls the internal pressure of the chamber 14 to a predetermined pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the chamber 14.

  A gas introduction part 7 is connected to one end of the discharge tube 2 of the plasma generator 1, and an etching gas G is introduced into the discharge tube 2 from the gas supply means 12 via the gas introduction part 7. In addition, a gas transfer unit 9 is connected to the other end of the discharge tube 2 of the plasma generator 1, and the gas transfer unit 9 is connected to the chamber 14 by a gas transfer tube 18. The gas transfer tube 18 is made of a material that resists corrosion caused by plasma products, such as quartz, stainless steel, ceramics, and fluororesin.

  One end of the introduction waveguide 4 is connected to the microwave generation means 13. The microwave generating means 13 generates a microwave M having a predetermined frequency (for example, 2.45 GHz) and radiates it toward the introduction waveguide 4.

The gas supply means 12 introduces an etching gas G into the discharge tube 2. For example, gases such as CF ₄ , NF ₃ , and O ₂ are introduced from the gas supply means 12 into the discharge tube 2 through a flow control valve (Mass Flow Controller, MFC) 19 and a gas introduction unit 7. ing. The introduction amount of the etching gas G can be adjusted by controlling the flow rate control valve 21 by the control means 15.

  The control means 15 performs not only control of the flow control valve 19 but also control of each element constituting the CDE device 100. For example, the pressure controller 17 is controlled to adjust the pressure inside the chamber 14, and the start / stop of the microwave generation means 13 and the decompression means 11 are controlled.

  The gas transfer pipe 18 is connected to the upper side wall of the chamber 14. A rectifying plate 20 is provided in the chamber 14. The rectifying plate 20 rectifies the flow of the plasma product introduced from the gas transport pipe 18 so that the amount of the plasma product on the processing surface of the workpiece Wf becomes uniform. . The rectifying plate 20 is a substantially circular plate-like body in which a large number of nozzle holes 21 are formed, and is fixed to the inner wall of the chamber 14.

Next, the operation of the CDE apparatus 100 will be described.
In addition, description of the effect | action of the plasma generator 1 mentioned above is abbreviate | omitted.
First, a workpiece Wf (for example, a semiconductor wafer) is carried into the chamber 14 by a transfer device (not shown), and is placed and held on the electrostatic chuck 16. Next, the inside of the chamber 14 is decompressed to a predetermined pressure by the decompression means 11. At this time, the pressure in the chamber 14 is adjusted by the pressure controller 17. Further, the inside of the discharge tube 2 communicating with the chamber 14 is also decompressed. Next, as described above, a plasma product is generated by the plasma generator 1 and introduced into the chamber 14 via the gas transfer unit 9 and the gas transfer pipe 18. The introduced plasma product is rectified by the rectifying plate 20 and reaches the surface of the workpiece Wf, and an etching process is performed. As described above, since the plasma product introduced into the chamber 14 becomes a neutral active species, the workpiece Wf is isotropically etched. The workpiece Wf for which processing has been completed is carried out of the chamber 14 by a transfer device (not shown). Thereafter, if necessary, the above-described etching process is repeated.

  In the above description, etching of a semiconductor wafer is taken as an example, but the present invention is not limited to this. For example, the present invention can be applied to pattern etching in manufacturing a liquid crystal display device, pattern etching in manufacturing a phase shift mask, and antireflection film etching in manufacturing a solar cell. In addition to etching, it can be applied to plasma generators, plasma processing apparatuses, and plasma processing methods used in a wide range of technical fields, such as surface hardening of metal parts, surface activation of plastic parts, and non-chemical sterilization. . In addition, with respect to these uses, other than the plasma generating apparatus, the plasma processing apparatus, and the plasma processing method according to the embodiment of the present invention described above can apply each known technique, and thus detailed description thereof is omitted.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.
As for the above-described specific examples, those skilled in the art appropriately modified the design are included in the scope of the present invention as long as they have the characteristics of the present invention.

For example, the shape, dimensions, material, arrangement, and the like of each element included in the plasma generator 1 and the plasma processing apparatus 100 are not limited to those illustrated, and can be changed as appropriate, and the gas used for the plasma processing And processing conditions can be changed as appropriate.
In addition, the elements included in each of the specific examples described above can be combined as much as possible, and combinations thereof are also included in the scope of the present invention as long as they include the features of the present invention.

It is a schematic cross section for demonstrating the plasma generator which concerns on embodiment of this invention. It is a model perspective view for demonstrating the external appearance of a plasma generator. It is a schematic cross section for demonstrating the axial direction cross section of FIG. It is a schematic cross section for demonstrating a CDE apparatus provided with a plasma generator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Plasma generator, 2 discharge tube, 3 plasma expansion member, 4 introduction | transduction waveguide, 7 gas introduction part, 9 gas conveyance part, 11 decompression means, 12 gas supply means, 13 microwave generation means, 14 chamber, 15 control Means, 16 electrostatic chuck, 17 pressure controller, 100 CDE apparatus, C plasma generation chamber, G etching gas, G1 gap, G2 gap, M microwave, P plasma, Wf

Claims (9)

A dielectric that partitions the decompressed space and the atmospheric pressure space, and a microwave waveguide, the microwave is introduced into the dielectric from the atmospheric pressure space via the microwave waveguide, and the decompressed A plasma generator for generating plasma on the side of the created space,
A plasma expansion member provided on the atmospheric pressure space side of the dielectric and having a dielectric constant lower than that of the dielectric is further provided, and the microwave is introduced into the dielectric via the plasma expansion member The plasma expansion member has an inner peripheral surface and an outer peripheral surface exposed to an atmospheric pressure space, and a gap is provided between the dielectric and the inner peripheral surface of the plasma expansion member. the plasma generating apparatus characterized by clearance is open to the atmosphere.   The cooling means further comprises a cooling means for cooling the plasma expansion member, and the cooling means surrounds the outer periphery of the plasma expansion member at and around the connecting portion between the plasma expansion member and the microwave waveguide. The plasma generator according to claim 1, wherein: The dielectric and the plasma expansion member are tubular members,
The plasma generator according to claim 1, wherein the dielectric is inserted substantially coaxially with the plasma expansion member.   The said plasma expansion member is provided so that the area | region where the said plasma of the said dielectric material generate | occur | produces may be covered, The plasma generator of Claims 1-3 characterized by the above-mentioned. The said gap is 0.5 mm or more and 2 mm or less, The plasma generator as described in any one of Claims 1-4 characterized by the above-mentioned. The plasma expansion member is made of quartz,
The dielectric is made of any one selected from the group consisting of alumina (Al2O3) or sapphire, boron nitride (BN), aluminum nitride, and yttrium aluminum garnet (YAG). The plasma generator according to any one of claims 1 to 5 . Comprising a plasma generating apparatus according to any one of claims 1-6, wherein the by caused plasma to a plasma treatment of the workpiece was feasible, a plasma processing apparatus according to claim. The plasma processing method according to claim 1 using a plasma generating apparatus according to any one of 6, to carry out the plasma treatment of the workpiece by said caused plasma, characterized by. 9. The plasma processing method according to claim 8 , wherein the plasma processing is etching of a semiconductor wafer, and NF3 (nitrogen trifluoride) gas is used as an etching gas.

Images