JP2005259633A - Microwave plasma discharge processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave discharge processing device whereby heavy plasma discharge can be obtained in a discharge processing chamber without having conventional matching adjusting mechanism circuit components in a high frequency wave line from a microwave oscillation source to a discharge processing part, and heavy power can be applied by a plurality of oscillation sources, without giving restrictions to the device design of the discharge processing chamber part while obtaining highly dense plasma under a low pressure required for forming plasma having a large diameter and a large capacity. <P>SOLUTION: A device structure whereby two discharge regions of a first microwave plasma discharge load part using a plurality of infinitely long dielectrics capable of obtaining highly dense plasma and a processing chamber discharge load part having a function capable of carrying out line propagation of a high frequency wave can be obtained is structured. In this structure, at least a part of the high frequency wave coupling part where the two discharge loads are coupled to the high frequency wave line is shared, and both discharge regions are connected as piping or a processing part structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention generates a large-diameter and large-capacity plasma discharge in a processing chamber, and does not require an adjustable matching function component using a stub or a magnetic field in a high-frequency line from a microwave oscillation source to a plasma load section. The present invention relates to a microwave plasma discharge processing apparatus that can efficiently introduce a microwave into a plasma load without generating a reflected wave.

  In the prior art 1, a cylindrical container shaft is placed at a position in the axial direction approximately n / 2 times the high frequency wavelength from a single surface of the cylindrical container on the high frequency line side in a cylindrical container made of a conductive material described in JP-A-8-236298. A microwave band high-frequency member introduced from the high-frequency line with a disk-shaped high-frequency transmitting member orthogonal to the high-frequency line direction side and a region opposite to the high-frequency line direction of the high-frequency transmitting member as a reduced pressure atmosphere for reaction processing Is a device for obtaining a high-frequency plasma gas discharge in the reduced-pressure atmosphere region (FIG. 1). This apparatus uses a cylindrical cavity resonance technique in the high-frequency resonance circuit technique, and can increase the energy efficiency and obtain a high-density plasma.

  In the prior art 2, the microwave band high frequency described in Japanese Patent Laid-Open Nos. 62-5600 and 62-99481 is orthogonal to the axis of the pressure reducing cylindrical container for reaction processing in the waveguide line from the waveguide line. The high frequency is reduced through a plate-shaped transmission window orthogonal to the cylindrical container shaft disposed opposite to the dielectric line through a dielectric line provided in parallel to the end face side, with a predetermined interval below the dielectric line. It is an apparatus for obtaining a high-frequency plasma gas discharge in a reduced-pressure cylindrical container for reaction treatment introduced into a cylindrical reaction chamber (FIG. 2). In this apparatus, a leakage electric field from the high-frequency electric field spread by the dielectric line to the lower side of the dielectric line is transmitted from the high-frequency transmission window to the reaction-processing cylindrical container, so that the area of the reaction-processing cylindrical container is uniform in the radial direction. A large plasma can be obtained.

  Prior art 3 is an improvement on the coupling between the high-frequency waveguide line and the dielectric line of the apparatus shown in FIG. 2 described in JP-A-11-067492. A disk-like shape orthogonal to a cylindrical container shaft that is arranged in parallel and coupled with a high frequency via an antenna portion in a direction intersecting with the line direction and arranged oppositely with a predetermined interval below the dielectric line. This is a device for obtaining a high-frequency plasma gas discharge in a reduced-pressure cylindrical container for reaction processing by introducing high-frequency into a reduced-pressure reaction chamber through a transmission window (FIG. 3). This device has effects such as miniaturization of the device, improvement of high-frequency matching, and improvement of electric field uniformity in the radial direction of the dielectric line by high-frequency propagation based on the point, and it is efficient and uniform in the radial direction of the reaction processing cylindrical container. Plasma with a large area can be obtained.

  In the prior art 4, slot holes are provided in the microwave line instead of the dielectric surface wave line of the prior art 2 described in Japanese Patent Application Laid-Open No. 2000-348898 to form an evanescent surface wave by leakage electrolysis, and a microwave drop window is provided. It is a surface wave plasma device that forms plasma via. In this apparatus, a plasma with a large uniform area in the radial direction of the reaction processing cylindrical container can be obtained by transmitting the high frequency electric field formed leaked by the slot line from the high frequency transmission window to the reaction processing cylindrical container.

Prior art 5 is a microwave discharge processing apparatus capable of generating large-capacity plasma having an infinitely long dielectric line structure described in International Publication No. 03/096769 pamphlet of international application by the present applicant. (FIG. 4) In this apparatus, the microwave from the microwave oscillation source can propagate infinitely in the load structure, so that it is not necessary to install a matching unit, and large power from a plurality of microwave oscillation sources is applied to the same load. It can be introduced.
JP-A-8-236298 JP-A-62-2005600 Japanese Patent Laid-Open No. 62-099481 Japanese Patent Laid-Open No. 11-067492 JP 2000-348898 A International Publication No. 03/096769 Pamphlet

  The industrial application range of high-frequency plasma gas discharge is concentrated in the field of semiconductor manufacturing or liquid crystal manufacturing at a large ratio. The main reason is due to the advantage that microfabrication and thin film formation can be performed in a gas phase. On the other hand, the main factors that prevent the use in the general industrial field are that the volume or area of the object to be processed is large and that a large volume of plasma needs to be generated, and that the apparatus is increased in size and power, resulting in an increase in apparatus cost. Further, in the semiconductor or liquid crystal manufacturing field, an increase in device cost accompanying an increase in the diameter of the semiconductor substrate and an increase in the area of the liquid crystal substrate has become a heavy burden.

  As described above, the use of plasma with a large area, large diameter, and large capacity requires firstly high plasma uniformity, secondly high efficiency, thirdly high power, and fourthly downsizing and cost reduction of the apparatus. is necessary.

  In order to obtain a large-area, large-diameter, large-capacity plasma for realizing the above device, it is necessary to reduce the discharge pressure that can sufficiently diffuse the plasma, but it suppresses the reduction in processing capacity due to the decrease in plasma density due to the low pressure. In order to do so, high density plasma is required.

  High-density plasma can be obtained even under low pressure, and there is no problem in introducing large high-frequency power into the same plasma load, and the high-frequency electric field surface can be formed largely and uniformly in the ionized gas plasma formation region. All of the energy loss can be transferred to the plasma load with high efficiency, the plasma stability is high, the equipment is miniaturized to the maximum, and there are few parts related to equipment maintenance for processing. An ionized gas plasma discharge treatment apparatus that satisfies the conditions is required.

  In order to generate high-density plasma relatively easily at low pressure, the frequency of the introduced high frequency is increased to increase the frequency, and the introduced power is increased to increase the electric field per unit area in the ionized gas plasma formation part. In order to satisfy the condition of low cost, it is necessary to use a generally used high frequency power source, and it is advantageous to use a microwave frequency in the GHz band.

  However, in the case of the microwave band, a loss in the high-frequency transmission line is increased in the coaxial line, so that a waveguide line having no loss is used. Waveguide lines depend on the frequency but have limited transmission power depending on the size or structure, and the waveguide line from the high-frequency oscillation part called the waveguide high-frequency three-dimensional circuit to the high-frequency coupling part with the load is physically As a result, the cost of the apparatus increases and the number of connecting portions of the high-frequency waveguide circuit increases, resulting in an increase in line loss. There is also a general problem that due to the shortened wavelength length, the high-frequency electric field surface in the load becomes dense.

  Prior art 1 is a structure in which high-frequency energy can be efficiently used for plasma discharge by a high-frequency hollow cylindrical resonance structure, but the end surface of the reduced-pressure plasma section forms the end surface of the cylindrical resonance waveguide and is orthogonal to the vertical axis of the cylindrical plasma. Since the cross-section is terminated, the uniformity of the plasma at the cross-section is difficult to control due to the projection of the high-frequency line mode in the cylindrical resonant waveguide, and the magnetic field is used to control the electron density. However, the device itself is increased in size and the cost of the device is significantly increased.

  In the prior arts 2, 3 and 4, a plasma formation region projected by introducing a high frequency from a waveguide line into a dielectric line or slot line and propagating the high frequency widely to the plasma generation region in the dielectric drop window However, this conventional technique using a dielectric line is a finite-length dielectric line having a termination as a high-frequency line, and a standing wave is formed by reflection from the termination in the line. In order to reduce the transmission loss, it is necessary to devise the size and shape of the line itself, and the electric field attenuation direction is generated in the high-frequency propagation direction. It is necessary to process the thickness and the like along with the shape of the track. Also, the slot line technique requires a large number of slot-shaped holes for large diameter and large capacity applications, and is not practical.

  In any of the above prior arts, the high-frequency line from the microwave oscillation source to the high-frequency load coupling portion to the plasma discharge load portion prevents high-frequency feedback to the oscillation source due to reflected low-frequency waves in the high-frequency line. In order to start or maintain discharge, a stub type or magnetic field control type matcher must be provided in the high frequency line, and the equipment cost is high. Therefore, there is a big problem that the device configuration is enlarged.

  Furthermore, in these technologies, when an oscillation source is used for a plurality of high frequency lines with the same load, a hunting phenomenon due to mutual interference occurs, resulting in instability of plasma discharge and large power loss. The necessity of using it arises, and a high-cost high-power single oscillation source is required.

  Prior art 5 is a technique that can solve the above-mentioned problem. However, in the shape of a large-diameter, large-capacity plasma discharge processing chamber, an infinitely long dielectric line must be formed, which causes restrictions on device design. That is a problem.

  In order to obtain a large-diameter plasma for large-area processing at low cost and maintain discharge, the processing chamber must first be reduced in volume. This is because an increase in equipment cost is inevitable unless the vacuum exhaust equipment required for decompression is downsized and reduced in price.

Next, in order to increase the speed and efficiency, it is necessary to introduce a large power into the processing chamber while creating a uniform high-frequency electric field in a portion corresponding to a large-area workpiece. However, power supply by a single high-frequency line using a single high-frequency power supply increases the price of the power supply and the high-frequency oscillation unit, so that the cost can be reduced only by a method of supplying power to the same load using a plurality of high-frequency lines.
However, high-frequency power supply to the same load by a plurality of high-frequency lines causes a problem that matching adjustment hunting occurs between the high-frequency lines. In order to solve this problem, it has a low-cost function that is electronically responsive and can be matched continuously on the high-frequency line to the high-frequency oscillation source with respect to impedance changes caused by current-voltage fluctuations on the plasma load side. I have to let it.
As described above, the plasma density per volume of the entire processing chamber can be ensured by introducing the high power and high frequency into the processing chamber. However, for large volume processing, an appropriate range of pressure conditions is set on the low vacuum side due to the effect of plasma diffusion, so that the maintenance of the electron density to obtain stable discharge is reduced and discharge instability is easily obtained. . In order to solve this problem, a high-density plasma region is required to maintain the discharge.

  However, obtaining a high-density plasma in the processing chamber region is synonymous with having a local electric field concentration portion, and particularly in the case of a large-capacity chamber, a high-frequency current is passed through the high-density plasma region. A short circuit occurs, and electromagnetic wave propagation to the entire large-volume processing chamber is suppressed. Therefore, it is necessary to have a configuration that does not have a local high-density plasma region in a large-volume processing chamber while having a high-density plasma region.

  The problems to be solved by the present invention are as follows. Microwave oscillation using a microwave plasma discharge using a microwave band that enables high-density plasma to be obtained even at low pressure, which is essential for large-diameter, large-capacity plasma formation. In addition to providing a device structure capable of plasma discharge using the discharge treatment chamber as a resonance structure without having a circuit component for the purpose of suppressing reflected low standing waves or maintaining discharge in the high-frequency line from the power source to the discharge treatment part, and providing higher power In order to solve this problem, it is an object of the present invention to provide an apparatus structure that can uniformly introduce high-frequency power from a plurality of oscillation sources into a discharge processing chamber.

  The present invention does not require the installation of an impedance matching device among microwave plasma discharge processing apparatuses, and can input high-frequency power from a plurality of high-frequency transmission lines to the same plasma load without mutual interference. The present invention relates to an apparatus capable of resonating with a large area, a large diameter, and a large capacity in a discharge processing chamber portion without loss due to reflection in propagation.

  The object of the present invention is to eliminate the above-mentioned problems of the prior art and to achieve high power, high plasma uniformity, high efficiency, and low cost, which are indispensable for generating a high-frequency plasma having a large area, large diameter, and large capacity. An object of the present invention is to provide a microwave plasma discharge device that satisfies the above requirements.

  In order to embody the content, the following method is used.

  In the entire plasma generator, which is the load seen from a single high-frequency oscillation source, the first microwave plasma discharge load section that can obtain high-density plasma and the processing chamber discharge load section that has the function of propagating high-frequency lines. The whole load structure part that can obtain two discharge areas is configured, and at least a part of the high-frequency coupling part between the two discharge loads and the high-frequency line is shared, and both discharge areas are pipes or processing parts. It is set as the structure connected as a structure.

  Furthermore, as a configuration of the first microwave plasma discharge load section, the ionized gas plasma itself proposed by the present applicant, which does not require a conventional matching device such as a stub movable or magnetic field matching, has dielectric characteristics and variable impedance. A non-reflective microwave that does not require a matching device based on Japanese Patent Application No. 2000-559714 (International Application No. PCT / JP99 / 03650), which can be applied and used to absorb all phase waves of electromagnetic waves from a high-frequency oscillation part by using a plasma load. Infinite-length dielectric described in International Application No .: PCT / JP03 / 05662 in which discharge load structure or microwave proposed by the present applicant can be propagated infinitely in the load structure portion, so that it is not necessary to install a matching unit A microwave discharge structure having a line structure is adopted.

  In addition, the processing chamber container itself grounded as the high-frequency propagation line of the processing chamber discharge load section has a resonance structure that functions as a waveguide propagation line, or the high-frequency introduced into the processing chamber container is propagated to the dielectric line surface. Structure.

  The operation of the present invention having the above configuration will be described. A high-density plasma that does not require a high-frequency matching unit is formed in the first microwave plasma discharge load section, and a part of the generated high-density plasma is generated in the process chamber that is a process chamber discharge load section connected under reduced pressure. Charged particles such as ions and electrons are introduced.

  On the other hand, the processing chamber shares a part of the high-frequency coupling portion in the first microwave plasma discharge load portion. For this reason, a part of the high frequency power from the single high frequency oscillation source is introduced into the processing chamber. The introduced high frequency is propagated in the processing chamber by a dielectric line formed in the processing chamber, or the processing chamber itself has a resonator structure depending on the structure of the processing chamber.

  In order to start normal discharge, initial gas ionization does not occur unless a high voltage is applied by a high electric field. However, in the configuration of the present invention, charged particles are introduced into the processing chamber from the first microwave plasma discharge load section. Therefore, it is not necessary to generate a high electric field in the processing chamber discharge load region. For this reason, in the processing chamber discharge region, it is only necessary to propagate a high electric field with a low electric field throughout the processing chamber region, thereby generating highly uniform low-density plasma in the entire processing chamber region.

In the processing chamber discharge load section, the discharge impedance changes depending on the installation of the processing sample, the pressure condition, the introduction of the processing chamber gas, etc., but when the high frequency oscillation source is viewed from the processing chamber discharge load section, the first microwave Since the self-alignment function based on the variable plasma impedance of the plasma discharge load unit operates as a matching circuit, electronically responsive matching is realized even in the process chamber discharge load.
According to the operating principle of the present invention, it is possible to connect a plurality of high-frequency oscillation sources by providing a first microwave plasma discharge load section having a function of matching a plurality of electron response speeds in one processing chamber. In addition, high power can be achieved at low cost.

  The above configuration eliminates all the problems of the prior art and enables high power, high plasma uniformity, high efficiency, and low cost, which are indispensable for generating high-frequency plasma with a large area, large diameter, and large capacity. At the same time, a satisfactory microwave plasma discharge processing apparatus is realized.

  With the configuration of the microwave discharge processing apparatus according to the present invention, a high-density plasma can be obtained under a low pressure necessary for forming a large-diameter, large-capacity plasma, and a microwave oscillation source without any restrictions on the apparatus design of the discharge processing chamber section A stable plasma discharge can be obtained in the entire discharge processing chamber without any conventional circuit components from the discharge processing to the discharge processing, and high power can be obtained by applying high-frequency power from multiple oscillation sources without any restrictions on the device structure. And a large processing volume can be realized at low cost.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  Embodiments of the present invention will be described below based on the first embodiment shown in FIG. FIG. 5 is a cross-sectional view of the vertical center portion of the microwave discharge processing apparatus according to the first embodiment of the present invention.

  The main part of this apparatus in FIG. 5 is that the processing chamber is closed by the upper connection flange “90”, the lower connection flange “91” and the processing section conductor tube “92” made of aluminum and can be evacuated from the pressure reducing port “93”. And a first microwave discharge vessel “101” which is connected to the upper connection flange “90” and includes a first microwave discharge vessel “101” which can be evacuated from the processing chamber by a microwave transmitting material. It is comprised by the discharge load part.

  The processing gas ionized by the plasma discharge is introduced with the flow rate adjusted in advance from the processing gas inlet “102” and the processing portion gas inlet “123”, and the high density by the microwave oscillated by the magnetron high frequency oscillation portion “2”. A plasma discharge region “94” and a low density plasma discharge region “95” are formed. Usually, the treated sample is placed in the low density plasma discharge region “95”.

  The microwave oscillated by the magnetron high-frequency oscillation unit “2” driven by the microwave power source “1” is on an aluminum conductor for enclosing the microwave discharge vessel “101” from the high-frequency coupling unit “42”. A magnetron high-frequency oscillating section “2” is connected to a first microwave discharge load section using a container composed of a flange “103”, a conductor lower flange “104”, and a coated conductor “43” as a resonator. .

  High-frequency waves introduced from the high-frequency coupling portion "42" propagate infinitely in the circumferential direction using the coated conductor "43" and the dielectric layer "53" provided in the space area on the side surface of the microwave discharge vessel "101" as a line. Then, the leakage electric field is generated in the microwave discharge vessel “101”, and a plasma discharge is obtained in the high-density plasma discharge region “94”.

  Due to the generation of ionized gas plasma, a plasma boundary surface is formed inside the microwave discharge vessel “101”. However, since the ionized gas plasma itself has a variable impedance, a part of the high frequency is absorbed by the ionized gas plasma. Some will be reflected by the plasma interface. The reflected wave is reflected and propagated alternately in the space cylindrical region between the coated conductor “43” and the dielectric layer “53” and the boundary surface of the high-density plasma discharge region “94”. The high-frequency line impedance in this region changes in conjunction with the ionized gas plasma impedance, and the line resonates in conjunction with the ionized gas plasma for the 1/4 wavelength impedance transformer matching circuit. Impedance matching is achieved, and electromagnetic energy is finally absorbed into the plasma load efficiently.

  Due to this operating principle, it is not necessary to install a conventional stub matching device or magnetic field matching device on the high-frequency line between the magnetron high-frequency oscillation unit “2” and the high-density plasma discharge region “94”, and a variable plasma impedance due to plasma can be obtained. Since it is used, the matching function operates at an electronic response speed.

  Charged particles such as ions and electrons and radicals or gas molecules in a metastable excited state obtained by plasma discharge in the first microwave discharge vessel “101” are introduced into the processing section chamber by a differential pressure. After being dispersed on the lower surface side of the dielectric plate “107” installed with a gap in the upper connection flange “90” by the plate “106”, it is diffused throughout the processing chamber.

  A part of the high frequency introduced from the high frequency coupling portion “42” is processed through the microwave-transmitting channel “121” opened to the space formed in the conductor lower flange “104” and the upper connection flange “90”. Propagates leakage to the chamber. Further, the microwave transmission channel “121” is vacuum-sealed through an O-ring by a quartz microwave transmission hole decompression seal ring window “105”.

  The high frequency waves leaking and propagating from the microwave transmission channel “121” to the processing chamber are propagated to the dielectric plate “107”, thereby forming a dielectric line and being dispersedly propagated in the processing chamber.

  As described above, charged particles such as ions and electrons obtained by plasma discharge in the first microwave discharge vessel “101” have already been introduced into the processing section chamber, and the dielectric plate “107”. The high frequency from the dielectric line caused by "will generate a low density plasma discharge region" 95 "in the entire processing chamber using these charged particles as the line.

  Regarding the matching function for the impedance variation of the low density plasma discharge region “95” due to the amount of sample in the processing chamber, pressure variation or discharge gas variation, etc., the impedance of the high density plasma discharge region “94” changes in conjunction with it. The entire high frequency matching will operate at an electronic response speed.

  In order to start normal discharge in the processing chamber as in this embodiment, initial gas ionization does not occur unless a high voltage is applied by a high electric field. However, in the configuration of the present invention, the first microwave plasma discharge vessel " Since charged particles are introduced into the processing chamber from 101 ", it is not necessary to generate a high electric field in the processing chamber discharge load region. For this reason, in the processing chamber discharge region, it is only necessary to propagate a high electric field with a low electric field throughout the processing chamber region, thereby generating highly uniform low-density plasma in the entire processing chamber region. Furthermore, in the processing chamber discharge load section, the discharge impedance changes depending on the installation of the processing sample, the pressure conditions, the introduction of the processing chamber gas, etc., but when the high frequency oscillation source is viewed from the processing chamber discharge load section, the first micro Since the self-alignment function based on the variable plasma impedance of the wave plasma discharge load part operates as a matching circuit, electronic response matching is realized even in the process chamber discharge load.

  Here, specific dimensions and capacities are shown. The microwave power source “1” is a DC high-voltage power source for 2.45 GHz magnetron oscillation, and the magnetron high-frequency oscillation unit “2” can oscillate microwaves with a maximum output of 750 W. The high frequency coupling portion “42” has an opening having a width of 70 mm and a height of 130 mm and is connected to a tubular coated conductor “43” having an outer diameter of φ100 and an inner diameter of φ90 mm. The dielectric layer “53” is made of tubular mica having an outer diameter of φ80 and an inner diameter of 70φ, and may be provided with a gap between the coated conductors “43” or may be in contact with the coated conductor “43”. The microwave discharge vessel “101” is made of quartz, and the quartz tube having a length of 180 mm, an outer diameter of 50 mm, and an inner diameter of 45 mm is closed at the top and bottom, and a quartz tube having an outer diameter of 10φ, an inner diameter of 7φ, and a length of 40 mm is integrally formed. ing. The aluminum conductor lower flange “104” has an outer diameter of 120φ and a thickness of 15 mm, and has six holes of φ20 mm as microwave transmission channels “121” located at a radius of 35 mm from the central axis.

  The upper connection flange “90” constituting the processing chamber has an aluminum outer diameter of 300 φ and a thickness of 20 mm, and a conductor lower flange “104” is fixedly connected to the upper portion with a bolt. The lower connecting flange “91” has an aluminum outer diameter of 300φ and a thickness of 20 mm, and a decompression port “93” is connected to the central portion of the NW25 vacuum pipe. The processing section conductor tube “92” is a stainless steel outer diameter 280φ, thickness 5 mm, length 400 mm, and a 1/4 inch SUS gas tank is welded to the side surface as a processing section gas inlet “123”. The upper connection flange “90” is provided with six holes of φ20 mm as microwave transmission channels “121” at a radius of 35 mm from the central axis, and is made of quartz microplate of φ18 thickness 3 mm for vacuum sealing. The wave transmission hole decompression seal ring window “105” is processed so as to be able to perform an O-ring seal. A dielectric plate “107” made of alumina having a diameter of 240 mm and a thickness of 3 mm is connected to the upper connection flange “90” by a bolt through a gap of 4 mm to the upper connection flange “90”. The baffle plate “106” made of alumina is connected to the upper connection flange “90” by a bolt so as to be 4 mm apart from the dielectric plate “107”.

  A test example of plasma generation in this example is as follows. Working vacuum conditions: 13 Pa to 1000 Pa, working gas is N2, O2 and mixed gas thereof, gas flow rate is 50 cc / min to 300 cc / min, input microwave power is 50 W to 750 W. The capacity of the evacuation system used was a rotary pump with a displacement of 1000 L / min, the vacuum was measured with a Pirani gauge on the evacuation line, and the pressure was adjusted by adjusting the open / close valve on the evacuation line. . Under all the above-mentioned generation conditions, plasma discharge was instantaneously obtained from the application of power, and an ionized gas plasma with uniform plasma emission over the entire vacuum vessel was obtained. In addition, no abnormality was observed in the magnetron oscillating portion even after long-term continuous operation for 1000 hours or more. Further, even if the pressure is continuously changed during the discharge or the discharge gas type is changed, the plasma discharge does not become unstable and can be obtained stably. At the same time, there is no abnormality in the magnetron oscillation part. The effect of was obtained.

  An embodiment of the present invention will be described below based on the second embodiment shown in FIG. FIG. 6 is a cross-sectional view of the vertical center portion of the microwave discharge processing apparatus in the second embodiment of the present invention.

  This embodiment is a modification of the first embodiment, and is for uniformly treating the surface of a large planar sample, and performing uniform plasma treatment on the entire large planar sample while minimizing the processing chamber volume as much as possible. It is intended.

  Usually, a plasma processing chamber for processing large planar samples requires a distance in the height direction to provide a high-frequency electrode and the like, which increases the manufacturing cost of the chamber, and requires an insulating structure around the high-frequency electrode, resulting in a complicated structure. It becomes. Furthermore, in order to form a uniform plasma on the surface of a flat sample, it is necessary to increase the size of the high-frequency electrode, and in order to equalize the high-frequency electric field in the sample peripheral area and avoid the influence of the wall surface, a large distance from the electrode is also required in the lateral direction of the processing chamber. The chamber volume increases because it must be taken. These inevitability has a problem that the cost of the apparatus is increased due to the necessity of increasing the capacity of the vacuum exhaust system in addition to the increase in the manufacturing cost of the chamber.

  In the method of the present embodiment, the upper portion “108” of the reduced pressure processing chamber is formed by cutting a 50 mm thick aluminum plate 30 mm in the depth direction, and the lower portion “109” of the reduced pressure processing chamber is a flat processing sample. It is made of an aluminum plate having a thickness of 25 mm, which is also used as a sample tray used as a sample transport for installing “110”, and is connected to an upper portion “108” of the reduced pressure processing chamber by O-ring to constitute a processing chamber. The depressurized exhaust is depressurized by a depressurized exhaust channel restraint “111” to which a vacuum exhaust pipe is connected to a plurality of exhaust holes provided on the side surface “108” of the depressurization processing chamber.

  The structure of the first microwave discharge load section, the principle of high-frequency propagation, and the operation of plasma discharge are the same as in the first embodiment.

  According to the method of the present invention, a uniform planar plasma having a large area can be formed by a high-frequency electric field from a dielectric line by the dielectric plate “107” in the processing chamber, and at the same time, a processing chamber structure for uniformly processing a planar sample surface is simplified. Furthermore, minimization of the processing chamber volume enables miniaturization of the vacuum exhaust system, which can greatly reduce the apparatus cost.

  Here, specific dimensions and capacities are shown. The upper part "108" of the reduced pressure processing chamber is a box type in which a groove of 30 mm depth is formed on one side of an aluminum plate having a thickness of 500 mm and a thickness of 50 mm except for an outer peripheral part of 25 mm. A plurality of exhaust holes are processed. A 400 mm square 5 mm thick alumina dielectric plate “107” is connected to the upper part “108” of the vacuum processing chamber via a 4 mm gap with a bolt, and a φ50 mm 3 mm thick alumina baffle plate “106” is connected to the upper part “108” of the vacuum processing chamber by a bolt so as to be 4 mm apart from the dielectric plate “107”. Other configurations are the same as those in the first embodiment.

  The operating state and impedance matching of the ionized plasma discharge in this embodiment are the same as those in the first embodiment. Moreover, the example of the stable discharge result of the plasma generation in the present embodiment is the same as that in the first embodiment.

  A processing efficiency test example in this embodiment is as follows. A 400 mm square liquid crystal glass substrate surface was treated as a sample, and the wettability evaluation of the surface after water plasma treatment for 5 minutes was performed. The processing conditions were microwave power of 750 W, processing gas (oxygen: 100 cc / min), processing pressure of 150 Pa, processing time of 5 minutes, and wettability with a contact angle of 0.5 degrees or less was obtained on the entire surface of the substrate. The substrate temperature after processing was measured at room temperature, and processing could be performed without increasing the substrate temperature.

  Embodiments of the present invention will be described below based on the third embodiment shown in FIG. FIG. 7 is a sectional view of the vertical center portion of the microwave discharge processing apparatus in the third embodiment of the present invention.

  This embodiment is a modification of the second embodiment, and is for uniformly treating the surface of a large planar sample, and is intended to perform uniform plasma treatment on the entire large planar sample while minimizing the processing chamber volume as much as possible. For this reason, the object is to introduce a large high-frequency power into the processing chamber at low cost, and a plurality of first microwave discharge loads are connected to the processing chamber.

  Usually, when high frequency lines from a plurality of microwave oscillation sources are connected to the same processing chamber in order to input large microwave power, interference between the high frequency lines is caused between the high frequency lines and is called a hunting phenomenon. Thus, the alignment becomes unstable in the processing chamber, and stable discharge cannot be obtained, and sometimes the plasma is lost.

  In the conventional matching method, it is impossible to follow the hunting due to interference in terms of speed, and a method of increasing the output of a single oscillation source is used to apply a large amount of power to the processing chamber. . However, in these methods, since a large amount of power is input to a single high-frequency line, measures for heat generation due to loss on the high-frequency line, noise countermeasures, and the like are required, leading to an increase in device cost. Furthermore, since the magnetron and the drive DC power supply have special specifications in the high-power magnetron oscillation, the cost is greatly increased.

  In the method of the present embodiment, two first microwave discharge loads are mounted on the upper portion “108” of the reduced pressure processing chamber, and the power input to the processing chamber is doubled as compared to the second embodiment.

  The operating state and impedance matching of the ionized plasma discharge in this embodiment are the same as those in the first embodiment and the second embodiment. In the test of plasma generation in this example, a stable discharge was obtained as in the second example as a result of applying 1500 W microwave power twice that of the second example.

  The operating state and impedance matching of the ionized plasma discharge in this embodiment are the same as those in the second embodiment. Moreover, the example of the stable discharge result of the plasma generation in the present embodiment is the same as that of the second embodiment.

A processing efficiency test example in this embodiment is as follows. A 400 mm square liquid crystal glass substrate surface was processed as a sample, and the wettability evaluation of the surface after water plasma treatment for 2 minutes was performed. When the processing conditions were a microwave power of 1500 W, a processing gas (oxygen: 100 cc / min), a processing pressure of 150 Pa, and a processing time of 5 minutes, wettability with a contact angle of 0.5 ° or less was obtained on the entire surface of the substrate. The substrate temperature after processing was measured at room temperature, and processing could be performed without increasing the substrate temperature.
(Other examples)
FIG. 8 shows a modification of the first embodiment. The fourth embodiment shows a method of increasing the microwave input power by connecting the first microwave discharge load sections in series. In the field of performing plasma treatment, there are etching, ashing, cleaning, CVD, modification treatment, semiconductor surface treatment, gas decomposition, light source, and the like.

  The present invention is not limited to the embodiments and embodiments described above, and includes various modifications without departing from the spirit and scope of the claims.

It is the discharge part schematic sectional drawing and block diagram of the conventional cylindrical resonance type magnetic field addition type microwave discharge processing apparatus. It is the discharge part schematic sectional drawing and block diagram of the conventional microwave discharge processing apparatus of a finite length dielectric material line | wire surface wave system. It is the discharge part schematic sectional drawing and block diagram of the microwave discharge processing apparatus using the conductor antenna in the conventional finite-length dielectric track | surface surface wave system. It is the discharge part schematic sectional drawing and block diagram of the microwave discharge processing apparatus in the conventional infinite length dielectric material line surface wave. 1 is a cross-sectional view of a vertical center portion of a microwave discharge processing apparatus in a first embodiment of the present invention. It is vertical center part sectional drawing of the microwave discharge processing apparatus in the 2nd Example of this invention. It is vertical center part sectional drawing of the microwave discharge processing apparatus in the 3rd Example of this invention. It is vertical center part sectional drawing of the microwave discharge processing apparatus in 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Microwave power supply 2 ... Magnetron high frequency oscillation part 3 ... Rectangular waveguide 4 ... Waveguide connection flange 5 ... Isolator 6 ... Power detection directional coupler 7 ... Impedance matching device 8 ... Circular rectangular conversion waveguide 9 ... Cylindrical cavity 10 ... solenoid coil 11 ... microwave transmission window 12 ... vacuum decompression vessel 13 ... processing object sample stage 14 ... shower plate 15 ... plasma load 16 ... plasma interface 17 ... air gap 18 ... dielectric line 19 ... antenna rod DESCRIPTION OF SYMBOLS 20 ... Process gas inlet 42 ... High frequency coupling part 43 ... Coated conductor 44 ... High frequency waveguide line 47 ... High frequency and high frequency traveling direction 53 ... Dielectric layer 58 ... O-ring 90 ... Upper connection flange 91 ... Lower connection flange 92 ... Processing portion Conductor tube 93 ... Depressurization port 94 ... High density plasma discharge region 95 ... Low density plasma discharge region 101 ... By microwave transmitting material One microwave discharge vessel 102 ... processing gas inlet 103 ... conductor upper flange 104 ... conductor lower flange 105 ... microwave transmission hole decompression seal ring window 106 ... baffle plate 107 ... dielectric plate 108 ... decompression treatment chamber upper part 109 ... decompression treatment Lower chamber portion 110 ... Processing sample 111 ... Vacuum exhaust channel restraint 121 ... Microwave transmission channel 122 ... Processing section microwave waveguide channel 123 ... Processing section gas inlet

Claims (5)

  In a structure for performing microwave plasma discharge in a reduced pressure processing chamber, the microwave oscillation source includes a first microwave plasma discharge load portion connected to the processing chamber and performing discharge separated from the chamber discharge load portion. At least a part of the processing chamber high-frequency load coupling part from which high frequency is introduced into the processing chamber discharge load part is shared as a part of the high-frequency load coupling part from which high frequency is introduced into the first microwave plasma discharge load part A microwave plasma discharge processing apparatus, wherein microwaves are introduced into both the first microwave plasma discharge load portion and the processing chamber discharge load portion from the same microwave oscillation source.   The line is closed so that at least a part of the high-frequency load coupling line to the first microwave plasma discharge load part is a surface wave dielectric line and has an infinite length as a propagation line. 2. The microwave plasma discharge treatment apparatus according to item 1.   3. The microwave plasma discharge processing apparatus according to claim 1, wherein at least a part of the high-frequency load coupling line to the processing chamber discharge load part is a surface wave dielectric line.   4. The microwave plasma discharge processing apparatus according to claim 1, wherein a stub type matcher and a magnetic field adjustment matcher are not provided in a high-frequency line from a microwave oscillation source to a discharge load section. The microwave plasma discharge treatment apparatus according to any one of claims 1 to 4, wherein the frequency of the microwave is 800 MHz or more and 5.8 GHz or less.

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