JP4883556B2 - Microwave transmission window, microwave plasma generator, and microwave plasma processing apparatus - Google Patents

Description

  The present invention relates to a microwave transmission window, a microwave plasma generation apparatus, and a microwave plasma processing apparatus, and more particularly, to a microwave transmission window excellent in reproducibility of a standing wave generated in the microwave transmission window and the same. The present invention relates to a microwave plasma generator and a microwave plasma processing apparatus.

  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, in manufacturing semiconductors and liquid crystal displays, 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. A microwave excitation type plasma source has a lower plasma potential than a high-frequency plasma source, and is therefore widely used for resist ashing without damage and anisotropic etching with a bias voltage applied.

  Semiconductor wafers to be processed and glass substrates for liquid crystal displays have been increasing in area year by year, so that a plasma generating apparatus having a high density and a uniform density over a large area is required to perform plasma processing on these.

In response to such a demand, various plasma processing apparatuses have been proposed.
FIG. 14 is a schematic diagram showing the structure of a microwave excitation type plasma processing apparatus examined by the inventor in the course of reaching the present invention.
This apparatus includes a processing chamber 10, a transmission window 30 made of a flat dielectric plate provided on the upper surface of the processing chamber 10, a microwave waveguide 20 provided outside the transmission window 30, and a transmission window. And a stage 16 for placing and holding a workpiece W such as a semiconductor wafer in a processing space below 30.

The processing chamber 10 can maintain a reduced pressure atmosphere formed by the vacuum exhaust system E, and a gas introduction pipe (not shown) for introducing a processing gas into the processing space is appropriately provided.
For example, when performing an etching process on the surface of the workpiece W using this plasma processing apparatus, first, the workpiece W is placed on the stage 16 with the surface facing upward. . Next, after the processing space is depressurized by the vacuum exhaust system E, an etching gas as a processing gas is introduced into the processing space. Thereafter, the microwave M is introduced from the microwave waveguide 20 to the slot antenna 20S in a state where the atmosphere of the processing gas is formed in the processing space.

  The microwave M is radiated from the slot antenna 20S toward the transmission window 30. The transmission window 30 is made of a dielectric such as quartz or alumina, and the microwave M propagates through the transmission window 30 and is radiated to the processing space in the processing chamber 10. At this time, the microwave M is fixed in the transmission window 30. A wave is formed. Plasma P of processing gas is formed by the energy of the microwave M radiated into the processing space in the processing chamber 10.

  In the plasma P excited in this manner, excited active species (plasma products) such as excited atoms, molecules, and free atoms (radicals) are generated when ions and electrons collide with molecules of the processing gas. Is done. These plasma products diffuse in the processing space as indicated by arrow A and fly to the surface of the workpiece W, and plasma processing such as etching is performed.

  By the way, as described above, the microwave M propagates through the transmission window 30 and is radiated to the processing space in the chamber 10. For this reason, the transmission window 30 is regarded as an important element related to the introduction of the microwave M, and the following technique has been proposed in the outer peripheral portion thereof.

Patent Document 1 discloses a technique for covering the outer peripheral portion of the transmission window with metal. The technique disclosed in Patent Document 1 prevents microwave leakage at the outer peripheral portion of the transmission window, thereby increasing the temperature rise efficiency and extending the life of the packing seal portion.
Patent Document 2 discloses a technique for covering an outer peripheral portion of a transmission window with a shield material. The technique disclosed in Patent Document 2 prevents the electromagnetic field from leaking to the outside of the chamber by a shielding material.
Patent Document 3 discloses a technique in which a standing wave control unit is provided on an outer peripheral part of a transmission window. In the technique disclosed in Patent Document 3, the standing wave electric field distribution inside the transmission window is optimized by the standing wave control unit to achieve uniform plasma processing.

  However, no consideration has been given to the thermal expansion of the transmission window and the standing wave formed in the transmission window.

FIG. 15 is an enlarged view of a microwave transmission window mounting portion of the microwave excitation type plasma processing apparatus shown in FIG. In this figure, the same parts as those in FIG. 14 are denoted by the same reference numerals, and detailed description thereof is omitted.
The transmission window 30 is hermetically attached to the processing chamber 10 by a sealing member 50 such as an O-ring. As described above, the standing wave 40 is formed in the transmission window 30.

  As described above, in the plasma processing apparatus, plasma of a processing gas is formed. At this time, the temperature of the transmission window 30 rises due to radiant heat from the plasma. As a result, although the transmission window 30 expands, the coefficient of thermal expansion between the dielectric transmission window 30 and the metal transmission window mounting portion is different, so that mutual interference during expansion can be prevented. A gap d is provided between the portion and the processing chamber 10.

  The standing wave 40 is affected by a gap d existing between the outer peripheral portion of the transmission window 30 and the processing chamber 10. That is, there is a problem that the reflected wave of the microwave varies depending on the presence / absence and size of the gap d, and the waveform of the standing wave changes. When the standing wave waveform changes, the distribution and density of the plasma P are affected, and the processing capability and product quality are also affected.

  Theoretically, if the gap d is constant, the same standing wave waveform can be reproduced. For this reason, it seems that it is possible to cope with each processing process by adjusting the process conditions. However, in practice, the gap d changes due to transportation, change with time, maintenance, etc. of the plasma processing apparatus, as described above. A problem arises in the reproducibility of the standing wave waveform.

  Here, Patent Documents 1 to 3 describe a technique of covering the outer periphery of the transmission window with a metal, a shield material, or the like. Thus, if the outer peripheral portion of the transmission window is covered, the gap d becomes 0 (zero), and it seems that the problem concerning the reproducibility of the standing wave waveform can be solved. However, if the outer periphery of the transmission window is covered with a structure such as a metal or a shielding material, there is a problem that a thermal stress is generated due to a difference in thermal expansion coefficient between the transmission window and these structures, and a gap is generated. . In this case, if the thermal stress is generated, the transmission window and the structure are damaged, and if a gap is formed, the electromagnetic field leaks, and in the case of Patent Document 3, the fluid leaks.

Further, as described in Patent Document 1, when the outer peripheral portion of the transmission window is covered with a thin film such as a vapor deposition film, the above-described problem of thermal stress hardly occurs. However, this thin film peels off while the transmission window repeatedly expands and contracts, causing problems such as leakage of the electromagnetic field.
JP 59-1000053 A JP 2002-246372 A JP 2002-280361 A

  The present invention improves the reproducibility of the standing wave waveform of the microwave formed in the transmission window. As a result, the distribution and density of the generated plasma are made uniform, and the reproducibility between plasma processing apparatuses is reduced. A microwave transmission window, a microwave plasma generation apparatus, and a microwave plasma processing apparatus that can solve the problem are provided.

According to one aspect of the invention,
A transmission window made of a dielectric;
A peripheral member made of a material that reflects the microwave and is provided so as to be in contact with the entire periphery of the outer peripheral portion of the transmission window;
With
The peripheral member has at least one movable joint portion where the joint portion is displaced, and the thermal stress due to thermal expansion of the transmission window is relieved by the displacement of the joint portion. The microwave transmission window used is provided.

According to another aspect of the present invention,
A processing chamber;
Means for introducing a processing gas into a space for generating plasma in the processing chamber;
The microwave transmitting window attached to the processing chamber;
With
There is provided a microwave plasma generator characterized in that plasma can be generated in a space where the plasma is generated by microwaves introduced through the microwave transmission window.

According to another aspect of the present invention,
Comprising the plasma generator,
There is provided a microwave plasma processing apparatus characterized in that plasma processing of an object to be processed can be performed by the generated plasma.

  ADVANTAGE OF THE INVENTION According to this invention, the reproducibility of the standing wave waveform of the microwave formed in a transmission window can be improved. As a result, there are provided a microwave transmission window, a microwave plasma generator, and a microwave plasma processing apparatus that can solve the problems of difference in distribution and density of generated plasma, reproducibility between plasma processing apparatuses, and the like. The industrial benefits are great.

Hereinafter, embodiments of the present invention will be described in detail with reference to specific examples.
FIG. 1 is an enlarged cross-sectional view of a mounting portion of a microwave transmission window according to an embodiment of the present invention. That is, this figure shows a part of the upper part of the processing chamber 10 of the plasma processing apparatus as shown in FIG. In this figure, the same elements as those described above with reference to FIG. 15 are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 2 is a schematic diagram showing a BB cross section of FIG.
As shown in FIGS. 1 and 2, a peripheral member 31 is provided on the outer peripheral portion of the transmission window 30 so as to contact the entire periphery. The peripheral member 31 can be generally formed of a metal such as aluminum, but is not limited thereto, and any material that reflects microwaves may be used. As described above, by bringing the peripheral member 31 into contact with the outer peripheral portion of the transmission window 30, even if the installation position of the transmission window 30 is changed, the microwave M is reflected on the contact surface, and the standing wave waveform is stabilized. As a result, the density and distribution of the plasma P are stabilized, and highly uniform plasma processing (for example, the ashing processing described above) can be performed.

  As shown in FIG. 2, the peripheral member 31 is provided with a movable joint portion 32. By providing such a joint portion 32, the above-described problem of thermal stress can be solved. That is, even if the transmission window 30 expands due to radiant heat from the plasma P, the joining portion 32 is displaced, so that generation of thermal stress can be eliminated or alleviated. Therefore, it is possible to maintain a stable standing wave waveform and perform plasma processing with high uniformity while preventing the transmission window 30 and the peripheral member 31 from being damaged.

  The peripheral member 31 is preferably formed of an elastic body. This is because if it is made of an elastic body, the adhesiveness with the transmission window 30 is increased, and the effect can be further exerted in the relaxation of thermal stress. The thickness of the peripheral member 31 is selected to be about 1 to 5 mm in consideration of elastic deformation and durability, but is not limited to this. Further, when the inner peripheral dimension of the peripheral member 31 is slightly smaller than the outer peripheral dimension of the transmission window 30 at normal temperature, the adhesion with the transmission window 30 can be further improved.

Hereinafter, the effect of the attachment part of the microwave transmission window of this embodiment is demonstrated, referring an experiment example.
FIG. 3 is a conceptual diagram for explaining the influence of the gap d existing between the outer peripheral portion of the transmission window 30 and the processing chamber 10. That is, this figure shows the upper part of the processing chamber 10 of the plasma processing apparatus as shown in FIG. 3, the same parts as those described in FIGS. 14 and 15 are denoted by the same reference numerals, and the description thereof is omitted.

  In the case of this specific example, the left outer peripheral portion (A portion) of the transmission window 30 abuts the inner wall surface of the processing chamber 10, and conversely, the right outer peripheral portion (B portion) is separated from the inner wall of the processing chamber 10 and a gap d is generated. Yes.

  The microwave M is generated by a microwave generation means (not shown) and then propagates through the microwave waveguide 20. The microwave M propagated through the microwave waveguide 20 is radiated from the slot antenna 20S toward the transmission window 30. The microwave M radiated toward the transmission window 30 propagates through the transmission window 30 to form a standing wave.

Here, the standing wave is affected by the gap d between the outer peripheral portion of the transmission window 30 and the processing chamber 10. That is, the reflection state of the microwave differs depending on the presence or absence and the size of the gap d, and the waveform of the standing wave changes.
FIG. 4A is an enlarged view of the left outer peripheral portion (A portion) of the transmission window 30.
As illustrated in the figure, when the transmission window 30 and the inner wall surface (metal surface) of the processing chamber 10 are in contact, the incident wave 60a is totally reflected on the contact surface.
FIG. 4B is an enlarged view of the right outer peripheral portion (B portion) of the transmission window 30.
As illustrated in the figure, when there is a gap d between the transmission window 30 and the inner wall surface (metal surface) of the processing chamber 10, a refracted wave 60b is generated when the incident angle θ of the incident wave 60a becomes shallow. . Conditions when the refracted wave is generated are related to the dielectric constant of the dielectric material which is the material of the transmission window and the dielectric constant of the gap (air). For example, if the material of the transmission window is quartz, the permittivity is 3.58, and the permittivity of the gap (air) is 1. Therefore, the incident angle θ of the limit incident wave 60a that generates the refracted wave 60b, so-called The critical angle is about 32 °.

  When the incident angle θ of the incident wave 60a is shallow (in the above example, smaller than about 32 °), a refracted wave is generated, and the reflection surface does not become the end face of the transmission window 30, but the processing chamber located beyond the gap d. 10 inner wall surfaces (metal surfaces). If the distance of the gap d varies, the position where the refracted wave 60b hits the inner wall surface (metal surface) of the processing chamber 10 changes and the position of the reflected wave 60c also varies. As described above, the reflection state of the microwave differs depending on the presence / absence and size of the gap d, and the waveform of the standing wave changes.

The inventor quantitatively evaluated the influence of the presence or absence of the gap d (the influence of the fluctuation of the standing wave waveform) by the fluctuation of the ashing rate.
FIG. 5 is a view of the processing chamber 10 as viewed from above. As shown in the figure, the introduced microwave M travels from Y <b> 1 to Y <b> 2 of the chamber 10.
6 and 7 are graphs showing the relationship between the position of the transmission window 30 (the presence or absence of the gap d) and the ashing rate.
Here, as the ashing conditions, oxygen was 300 sccm as the ashing gas, the processing pressure was 40.5 Pa, and the microwave power was 2 kW.

  FIG. 6A is a graph showing fluctuations in the ashing rate when the transmission window 30 is brought into contact with the inner wall surface (metal surface) of the Y2 side processing chamber 10 shown in FIG. 6A corresponds to the X1-X2 axis in FIG. 5, and the Y-axis in FIG. 6A corresponds to the Y1-Y2 axis in FIG. The horizontal axis of the graph indicates the measurement position of the ashing rate, and the zero point corresponds to the center of the processing chamber 10, that is, the point c in FIG. As is clear from FIG. 6A, the fluctuation of the ashing rate in this case is plus or minus 14.5% from the average value.

  FIG. 6B is a graph showing fluctuations in the ashing rate when the transmission window 30 is arranged at c in FIG. 5, that is, at the center of the processing chamber 10. As is apparent from FIG. 6B, the fluctuation of the ashing rate in this case is plus or minus 19.1% from the average value.

  FIG. 6C is a graph showing the fluctuation of the ashing rate when the transmission window 30 is brought into contact with the inner wall surface (metal surface) of the processing chamber 10 on the Y1 side in FIG. As is clear from FIG. 6C, the fluctuation of the ashing rate in this case is plus or minus 22.2% from the average value.

  FIG. 7A is a graph showing fluctuations in the ashing rate when the transmission window 30 is brought into contact with the inner wall surface (metal surface) of the processing chamber 10 on the X1 side in FIG. As is apparent from the figure, the fluctuation of the ashing rate in this case is plus or minus 16.8% from the average value.

  FIG. 7B is a graph showing fluctuations in the ashing rate when the transmission window 30 is brought into contact with the inner wall surface (metal surface) of the processing chamber 10 on the X2 side in FIG. As is apparent from the figure, the fluctuation of the ashing rate in this case is plus or minus 15.8% from the average value.

  6 and 7, first of all, it can be seen that if the installation position of the transmission window 30 changes, the fluctuation range of the ashing rate also changes. This is because, as described above, if the installation position of the transmission window 30 changes, the gap d changes and the standing wave waveform also changes. Second, if there is a gap d on the front side in the traveling direction of the microwave M, the influence is small, and if there is a gap d on the far side in the traveling direction, the influence is large, and the gap d perpendicular to the traveling direction of the microwave M is large. Is less affected than the clearance d in the traveling direction. This means that the fluctuation of the ashing rate can be suppressed by eliminating or controlling the gap d in a specific direction (back side in the traveling direction).

  On the other hand, according to the structure of this embodiment illustrated in FIGS. 1 and 2, even if the installation position of the transmission window 30 is changed by bringing the peripheral member 31 into contact with the outer peripheral portion of the transmission window 30. The microwave M is reflected by the contact surface, and the standing wave waveform is stabilized. As a result, the density and distribution of the plasma P are stabilized, and highly uniform plasma processing (for example, the ashing processing described above) can be performed.

FIG. 8 is an enlarged view illustrating the structure of the joint portion 32 of the peripheral member 31 illustrated in FIGS. 1 and 2.
In the case of this specific example, the joint portion 32 is formed by a slope 32a and a slope 32b, and is slidable while being in contact with each other. As described above, since the joining portion 32 is in contact, the microwave M does not leak to the outside from this portion. When the transmission window 30 is thermally expanded, the generation of thermal stress can be eliminated or alleviated by shifting the inclined surfaces 32a and 32b. For convenience of explanation, the slope 32b is on the transmission window 30 side, but the slope 32a may be on the transmission window 30 side.

FIG. 9 is a schematic diagram illustrating a second specific example of the joint portion 32.
In the case of this specific example, the joint portion 32 is formed by a step 32c and a step 32d so as to contact each other. As described above, since the joining portion 32 is in contact, the microwave M does not leak to the outside from this portion. When the transmission window 30 is thermally expanded, the generation of thermal stress can be eliminated or alleviated by shifting the steps 32c and 32d. The gap S1 is for preventing interference when the steps 32c and 32d are displaced. For convenience of explanation, the two gaps S1 have the same size, but need not necessarily have the same size. Further, when the peripheral member 31 is mounted on the outer periphery of the transmission window 30 at room temperature, the gap S1 can be appropriately selected so as to have a dimension of 0 or larger. In the description, the step 32d is on the transmission window 30 side, but the step 32c may be on the transmission window 30 side.

FIG. 10 is a schematic diagram illustrating a third specific example of the joint portion 32.
In the case of this specific example, the joining portion 32 is formed by the overlapping portion 32e and the overlapping portion 32f, and is in contact with each other. As described above, since the joining portion 32 is in contact, the microwave M does not leak to the outside from this portion. When the transmission window 30 is thermally expanded, generation of thermal stress can be eliminated or alleviated by shifting the overlapping portion 32e and the overlapping portion 32f. The dimensions of the overlapping portion 32e and the overlapping portion 32f can be appropriately selected in consideration of the thermal expansion dimension of the transmission window 30. In the case of this embodiment, if the thickness of the peripheral member 31 is reduced to some extent, the overlapping portion 32e can be formed with the flexibility of the member itself. Therefore, there is an advantage that a special process for the joint portion 32 is not necessary. For convenience of explanation, the overlapping portion 32f is on the transmission window 30 side, but the overlapping portion 32e may be on the transmission window 30 side.

  In the specific examples shown in FIGS. 9 and 10, a space (S1 or S2 portion) is formed between the peripheral member 31 and the transmission window 30. Therefore, although a refracted wave is generated in this portion, the influence is small because this space is small. Further, as described with reference to FIG. 3, there is a direction that is not easily affected by the traveling direction of the microwave M. For this reason, if the installation direction of the space is set to a direction that is not easily affected, the influence of the refracted wave can be further suppressed.

  In addition, the shape of the junction part 32 is not restricted to what was illustrated in FIGS. 8-10, What has the same function can be selected suitably. Moreover, although what was illustrated in FIGS. 8-10 is the thing of the junction part 32 of one place, it is not limited to this, The number of junctions can be determined suitably.

Fig.11 (a) is an enlarged view of the microwave transmission window attachment part concerning the other embodiment of this invention. Moreover, FIG.11 (b) is a figure which shows CC cross section of Fig.11 (a).
Elements similar to those described above with reference to FIG. 4 are given the same reference numerals and description thereof is omitted.
A peripheral member 31 is provided in contact with the outer peripheral portion of the transmission window 30. Here, for convenience of explanation, the shape of the joint portion (32e, 32f) is illustrated in FIG. 10, but is not limited to this, and has the same function including the other examples described above. Can be appropriately selected.
In this specific example, an urging member 34 is provided between the peripheral member 31 and the inner wall surface (metal surface) of the processing chamber 10. Since the peripheral member 31 is brought into contact with the transmission window 30 by such an urging member 34, the adhesion can be improved and an effect can be expected for the relaxation of thermal stress. Further, even when a plurality of joint portions are provided or when the elastic force of the peripheral member 31 is small, by providing such an urging member 34, the adhesion between the peripheral member 31 and the transmission window 30 can be kept high. it can. The urging member 34 may be, for example, an elastic body such as a coil spring, a leaf spring, a torsion coil spring, or rubber, but is not limited thereto. For example, a member that generates an urging force by air pressure or electromagnetic force may be provided. The number of urging members 34 is not limited to that shown in the figure, and the arrangement position can be appropriately selected.

  The specific example of the microwave transmission window that can be used in the present invention has been described above with reference to FIGS. However, the present invention is not limited to those using these specific examples. For example, although the microwave transmission window has a disk shape, the plane shape can be arbitrarily selected from triangles, rectangles, polygons, ellipses, etc. Also, the thickness dimension need not be constant and the center It is possible to arbitrarily select a thick part or a thick peripheral part.

  FIG. 12 is a schematic diagram showing the structure of the microwave plasma generator of the embodiment of the present invention. The plasma generator includes a processing chamber 10, a transmission window 30 made of a flat dielectric plate provided on the upper surface of the processing chamber 10, a microwave waveguide 20 provided outside the transmission window 30, Have

The processing chamber 10 can maintain a reduced pressure atmosphere formed by a vacuum exhaust system (not shown), and a gas introduction pipe (not shown) for introducing a processing gas into the processing space is appropriately provided.
In this microwave plasma generator, first, the processing space is decompressed by an unillustrated evacuation system, and then a processing gas is introduced into the processing space. Thereafter, the microwave M is introduced from the microwave waveguide 20 to the slot antenna 20S in a state where the atmosphere of the processing gas is formed in the processing space.

  The microwave M is radiated from the slot antenna 20S toward the transmission window 30. The transmission window 30 is made of a dielectric such as quartz or alumina, and the microwave M propagates through the transmission window 30 to form a standing wave in the transmission window 30. At this time, as described above, since the peripheral member 31 is in contact with the outer peripheral portion of the transmission window 30, the reflection surface is stabilized and the standing wave waveform is also stabilized. Therefore, the density and distribution of the plasma P are stable, and highly uniform plasma can be generated. For the sake of convenience, the peripheral member 31 has been described with reference to FIG. 11, but the peripheral member 31 is not limited to this, and a member having the same function including those described above can be appropriately selected and used.

  The microwave M radiated toward the transmission window 30 is radiated to the processing space in the processing chamber 10. Then, a plasma P of the processing gas is formed by the energy of the emitted microwave M. In the plasma P thus excited, ions and electrons collide with the molecules of the processing gas, so that excited active species (plasma products) such as excited atoms, molecules, and free atoms (radicals) are present. Generated.

FIG. 13 is a schematic diagram showing the structure of the microwave plasma processing apparatus according to the embodiment of the present invention. Since the part of the microwave plasma generator is the same as that described with reference to FIG. 12, the same reference numerals are given to the same elements, and detailed description thereof is omitted.
A stage 16 for mounting and holding a workpiece W such as a semiconductor wafer in a processing space below the transmission window 30 is provided. Further, a vacuum exhaust system E for exhausting the inside of the processing chamber 10 under reduced pressure is connected to the bottom of the processing chamber 10.

  In this microwave plasma processing apparatus, as shown by the arrow A, excited active species (plasma products) such as excited atoms, molecules, and free atoms (radicals) generated by the microwave plasma generation apparatus are represented. The inside of the processing space is diffused, and is made to fly to the surface of the workpiece W, and plasma processing such as etching is performed. At this time, as described above, since the peripheral member 31 is in contact with the outer peripheral portion of the transmission window 30, the reflection surface is stabilized and the standing wave waveform is also stabilized. Therefore, the density and distribution of the plasma P are stable and a highly uniform plasma can be generated. As a result, stable plasma processing can be performed. For the sake of convenience, the peripheral member 31 has been described with reference to FIG. 11, but the peripheral member 31 is not limited to this, and a member having the same function including those described above can be appropriately selected and used.

  The embodiments of the present invention have been described with reference to specific examples. However, the present invention is not limited to these specific examples.

  For example, the elements such as the waveguide used in the present invention are not limited to the illustrated shapes and sizes, and the cross-sectional shape, wall thickness, opening shape and size, etc. are appropriately changed to achieve the same effects. And is included within the scope of the present invention.

  Further, the shape and size of the processing chamber, or the arrangement relationship of the stage and the like are not limited to those shown in the drawings, and can be appropriately determined in consideration of the contents and conditions of the plasma processing. Further, the transmission window may be provided not only on the upper surface of the plasma generation chamber but also on the side surface and the lower surface, or a combination thereof. That is, a plurality of transmission windows may be attached to the plasma generation chamber. This makes it possible to form a large-area plasma having a uniform or predetermined density distribution according to the shape and size of the object to be processed.

  The introduction of the microwave is not limited to that using a waveguide, and for example, a device such as a radial line slot antenna may be used.

  Furthermore, in the specific examples described above, only the configuration of the main part of the microwave transmission window has been described. However, the present invention is applicable to all microwave plasma generators and microwave plasma treatments having such a microwave transmission window. For example, any of a microwave plasma generator and a microwave plasma processing apparatus realized as an etching apparatus, an ashing apparatus, a thin film deposition apparatus, a surface treatment apparatus, a plasma doping apparatus, and the like are included in the scope of the present invention. The

It is an enlarged view of the microwave transmission window attachment part concerning the embodiment of this invention. It is a figure which shows the BB cross section of FIG. It is a conceptual diagram for demonstrating the influence of the clearance gap which exists between the outer peripheral part of a permeation | transmission window, and a processing chamber. It is an enlarged view of the permeation | transmission window outer peripheral part. It is the figure which looked at the processing chamber 10 from the upper direction. It is a graph showing the relationship between the position of the transmission window 30 (the presence or absence of the gap d) and the ashing rate. It is a graph showing the relationship between the position of the transmission window 30 (the presence or absence of the gap d) and the ashing rate. 3 is an enlarged view of a joint portion of a peripheral member 31. FIG. It is a figure which shows the 2nd Example of a junction part. It is a figure which shows the 3rd Example of a junction part. It is an enlarged view of the microwave transmission window attaching part concerning other embodiments of the present invention. It is a schematic diagram showing the structure of the microwave plasma generator of the Example of this invention. It is a schematic diagram showing the structure of the microwave plasma processing apparatus of the Example of this invention. It is a schematic diagram showing the structure of the microwave excitation type | mold plasma processing apparatus which this inventor examined in the process leading to this invention. It is an enlarged view of the microwave transmission window attachment part of the microwave excitation type | mold plasma processing apparatus represented to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Processing chamber 20 Microwave waveguide 20S Slot antenna 30 Transmission window 31 Peripheral member 32 Joint part 32a, 32b Slope 32c, 32d Level | step difference 32e, 32f Superposition part 34 Energizing member 40 Standing wave 60a Incident wave 60b Refracted wave 60c Reflection Wave M Microwave P Plasma W Workpiece

Claims (6)

A transmission window made of a dielectric;
A peripheral member made of a material that reflects the microwave and is provided so as to be in contact with the entire periphery of the outer peripheral portion of the transmission window;
With
The peripheral member has at least one movable joint portion where the joint portion is displaced, and the thermal stress due to thermal expansion of the transmission window is relieved by the displacement of the joint portion. Microwave transmission window used .   The microwave transmission window according to claim 1, wherein the joint portion has a movable contact portion.   The microwave transmitting window according to claim 1, wherein the peripheral member is made of an elastic body.   The microwave transmission according to any one of claims 1 to 3, further comprising an urging means for urging the peripheral member toward the transmission window outside the peripheral member. window. A processing chamber;
Means for introducing a processing gas into a space for generating plasma in the processing chamber;
The microwave transmitting window according to any one of claims 1 to 4, attached to the processing chamber;
With
A microwave plasma generator characterized in that plasma can be generated in a space where the plasma is generated by microwaves introduced through the microwave transmission window. A plasma generator according to claim 5,
A microwave plasma processing apparatus, characterized in that plasma processing of an object to be processed can be performed by the generated plasma.

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