JP6155455B2 - Electrode for atmospheric pressure plasma generation, atmospheric pressure plasma generation apparatus, and method for producing atmospheric pressure plasma workpiece using the same - Google Patents

Description

  The present invention relates to an atmospheric pressure plasma generation electrode, an atmospheric pressure plasma generation apparatus, and a method for manufacturing an atmospheric pressure plasma workpiece using the same.

As one method for precisely processing a surface to be processed, an atmospheric pressure plasma method using plasma generated under atmospheric pressure is known. In the atmospheric pressure plasma method, a process gas is supplied to a predetermined electrode to which a high-frequency voltage is applied, a radical based on the process gas is generated together with the atmospheric pressure plasma, and a substance generated by a radical reaction between the radical and a surface to be processed is removed. This is a method of processing the surface to be processed (see, for example, Patent Document 1).
As an electrode used in such an atmospheric pressure plasma method, an electrode that can efficiently process a surface to be processed is desirable.

JP 2010-251163 A

  An object of the present invention is to provide an atmospheric pressure plasma generating electrode and an atmospheric pressure plasma generating apparatus that can efficiently process a surface to be processed by atmospheric pressure plasma, and a method of manufacturing an atmospheric pressure plasma workpiece using the same. That is.

  The electrode for generating atmospheric pressure plasma of the present invention includes a plate-shaped bottom portion having an upper surface and a lower surface, a tubular side wall portion connected to the outer peripheral portion of the bottom portion and extending upward, an upper surface of the bottom portion, and an inner surface of the side wall portion A hollow portion surrounded by the first gas inner flow path which is located in the hollow portion and through which the first process gas flows, and is located in the side wall portion and connected to the first gas inner flow path. An electrode portion having one through-hole, a tubular body surrounding the outer surface of the side wall portion on the inner surface through a gap, and a first gas outer side located in the gap and connected to the at least one through-hole A flow path, and at least one first gas supply port located between the bottom and the lower end of the tubular body and connected to the first gas outer flow path, , The first portion in the hollow portion A second gas flow path through which the second process gas flows, and at least one second gas supply located at the bottom and connected to the second gas flow path. And a mouth.

  An atmospheric pressure plasma generation apparatus according to the present invention includes the above-described atmospheric pressure plasma generation electrode, a support base that is positioned below the atmospheric pressure plasma generation electrode and supports the workpiece, and below the workpiece. A counter electrode positioned opposite to the atmospheric pressure plasma generating electrode; voltage applying means for applying a voltage between the atmospheric pressure plasma generating electrode and the counter electrode; and the first gas inner flow path. And a gas supply means for supplying the second process gas to the second gas flow path.

  The method for producing an atmospheric pressure plasma workpiece according to the present invention is a method for producing an atmospheric pressure plasma workpiece using the atmospheric pressure plasma generator described above, wherein the first process gas is produced by the gas supply means. Supplying the second process gas to the second gas flow path, and supplying the first process gas from the at least one first gas supply port. Supplying the second process gas to the processing surface from the at least one second gas supply port, and supplying the atmospheric pressure plasma generating electrode by the voltage applying means. Applying a voltage between the counter electrode and generating atmospheric pressure plasma.

  According to the present invention, there is an effect that a processing surface can be efficiently processed by atmospheric pressure plasma. The present invention is suitable for the so-called atmospheric pressure plasma CVM (Chemical Vaporization Machining) method.

It is a schematic explanatory drawing which shows the atmospheric pressure plasma generator which concerns on one Embodiment of this invention. FIG. 2 is a partial enlarged cross-sectional view showing a lower part of an atmospheric pressure plasma generation electrode in the atmospheric pressure plasma generator of FIG. 1. It is the figure which looked at the electrode for atmospheric pressure plasma generation of FIG. 2 from the arrow A direction. FIG. 3 is a partial enlarged cross-sectional view showing a part of the bottom of the atmospheric pressure plasma generation electrode of FIG. 2. It is a partial expanded sectional view which shows the lower part of the electrode for atmospheric pressure plasma generation which concerns on other embodiment of this invention.

<Electrode for atmospheric pressure plasma generation>
Hereinafter, an atmospheric pressure plasma generation electrode (hereinafter sometimes referred to as an “electrode”) according to an embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, the atmospheric pressure plasma generation electrode 1 of the present embodiment is provided in an atmospheric pressure plasma generator 10 described later, and includes an electrode portion 2. As shown in FIG. 2, the electrode portion 2 of the present embodiment includes a plate-like bottom portion 21, a tubular side wall portion 22, a hollow portion 23 surrounded by the bottom portion 21 and the side wall portion 22, and a hollow portion 23. It has the 1st gas inner side flow path 24 located, and the at least 1 through-hole 25 located in the side wall part 22. As shown in FIG. Hereinafter, each component of the electrode part 2 is demonstrated in order.

  The bottom 21 of the present embodiment has an upper surface 21a and a lower surface 21b. Further, as shown in FIG. 3, the bottom portion 21 of the present embodiment is circular in a bottom view. The bottom view means a state in which the bottom portion 21 is viewed from the bottom surface 21b side. Note that the shape of the bottom portion 21 in the bottom view is not limited to a circle, and may be a polygon such as a quadrangle. The bottom 21 is plate-shaped, but need not be a flat surface. For example, a curved surface in which the lower surface 21b is convex downward may be used.

  The side wall portion 22 of this embodiment is connected to the outer peripheral portion of the bottom portion 21 and extends upward. More specifically, the side wall portion 22 of the present embodiment is connected to the outer peripheral portion of the upper surface 21a of the bottom portion 21 and extends upward. The upper side means the upstream side in the flow direction of the process gas described later with respect to the bottom portion 21.

  Further, the side wall portion 22 of this embodiment is formed integrally with the bottom portion 21. According to such a configuration, the strength of the electrode unit 2 can be improved. In addition, the side wall part 22 can also be comprised with the bottom part 21 and another member as needed. Further, the side wall portion 22 of the present embodiment is connected to the end portion of the outer peripheral portion of the upper surface 21 a of the bottom portion 21. In addition, the side wall part 22 may be connected inside the edge part of the outer peripheral part of the upper surface 21a of the bottom part 21. FIG.

  The side wall part 22 of this embodiment is substantially circular tubular (substantially cylindrical). In addition, the shape of the side wall part 22 is not limited to a substantially circular tubular shape, and can be made into a desired shape corresponding to the shape of the bottom part 21 as long as it is tubular.

  The side wall part 22 of the present embodiment has a lower side wall part 221 and an upper side wall part 222 having an outer diameter larger than that of the lower side wall part 221 in order from the bottom 21 side upward.

  The hollow portion 23 of the present embodiment is surrounded by the upper surface 21 a of the bottom portion 21 and the inner surface 22 a of the side wall portion 22. The hollow portion 23 of the present embodiment is substantially circular in a cross-sectional view perpendicular to the longitudinal direction. In addition, the shape of the hollow part 23 in the cross-sectional view mentioned above is not limited to a substantially circular shape, For example, polygonal shapes, such as a square, may be sufficient.

The first gas inner flow path 24 of the present embodiment is a portion through which the first process gas flows. Examples of the first process gas include fluorine atom-containing compound gases such as CF ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₈ , CClF ₃ , SF ₆ , and CHF ₃ ; Cl ₂ , BCl ₃ , CCl ₄ And halogen-based gases such as chlorine atom-containing compound gases, etc., and these may be used alone or in combination of two or more. The first process gas may be a mixed gas of these exemplified process gases and a so-called carrier gas. The carrier gas means a gas introduced for starting discharge and maintaining discharge. Examples of the carrier gas include rare gases such as He, Ne, Ar, and Xe, and these may be used alone or in combination. Further, O ₂ may be mixed with the mixed gas in order to promote dissociation of the process gas. These exemplified gases can be used in a desired combination according to the workpiece 100 described later.

  Although the ratio (mixing ratio) of the process gas in the mixed gas is not particularly limited, for example, the ratio of the process gas in the mixed gas may be 0.1 to 10%. In particular, when the ratio of the process gas in the mixed gas is 0.1 to 5%, the rare gas can be sufficiently excited.

  The through hole 25 of the present embodiment is located in the lower side wall portion 221 of the side wall portion 22 and is connected to the first gas inner flow path 24. Further, the through hole 25 of the present embodiment penetrates between the inner surface 22a and the outer surface 22b of the lower wall portion 221.

  Here, the electrode part 2 has a plurality of through-holes 25, and the plurality of through-holes 25 are preferably positioned at substantially equal intervals along the outer peripheral direction at the same height. The electrode part 2 of the present embodiment has four through holes 25. The four through holes 25 are positioned at substantially equal intervals along the outer peripheral direction of the lower wall portion 221 at the same height. According to such a configuration, the first process gas can be smoothly and uniformly passed through the first gas outer flow path 4 described later while maintaining the strength of the side wall portion 22. The number of through holes 25 is not limited to four, and the heights of the plurality of through holes 25 and the distances between them are not limited to the above-described configuration.

  As a constituent material of the electrode part 2 which has the structure mentioned above, metals, such as aluminum, copper, iron, silver, these alloys, etc. are mentioned, for example.

  On the other hand, in addition to the electrode part 2 described above, the electrode 1 of the present embodiment is positioned in the gap 31 and the tubular body 3 that surrounds the outer surface 22b of the side wall part 22 with the inner face 3a via the gap 31. 1 gas outer side flow path 4, and at least 1 1st gas supply port 5 located between the bottom part 21 and the lower end part 33 of the tubular body 3 are further provided. In other words, the first gas supply port 5 is formed by arranging the bottom 21 and the lower end 33 of the tubular body 3 with a gap 31 therebetween.

  The tubular body 3 of the present embodiment surrounds the outer surface 22 b of the lower wall portion 221 of the side wall portion 22. Moreover, the tubular body 3 of this embodiment is attached to the electrode part 2 in the following states. That is, the side wall part 22 described above further includes a step part 223 connected to each of the lower side wall part 221 and the upper side wall part 222. The step part 223 is located on the upper wall part 222 side, and has a locking part 223a that is convex on the bottom part 21 side. The tubular body 3 of the present embodiment is a circular tube (cylindrical), and is attached to the electrode portion 2 in a state where the upper end portion 32 side is locked to the locking portion 223a.

  The lower end portion 33 of the tubular body 3 of the present embodiment is located below the bottom portion 21 of the electrode portion 2. According to such a configuration, the flow of the first process gas can be guided downward without diverging in the plane direction to form a so-called microchamber, and atmospheric pressure plasma can be stably generated. It becomes. Note that the downward direction means the downstream side in the flow direction of the process gas with respect to the bottom portion 21. For example, the lower end 33 may be positioned below the bottom 21 by about 50 μm to 200 μm.

  The tubular body 3 having the above-described configuration is preferably made of an insulating material. Examples of the insulating material include ceramics such as alumina and Teflon (registered trademark). In addition, the tubular body 3 can also be comprised with materials other than an insulating material. Examples of materials other than the insulating material include metals such as copper, iron, and silver, and alloys thereof. The tubular body 3 is preferably made of a material having plasma resistance and high strength, and alumina can be exemplified as such an example.

  The first gas outer channel 4 of the present embodiment is connected to at least one through hole 25, and the first gas supply port 5 of the present embodiment is connected to the first gas outer channel 4. According to such a configuration, the first process gas described above can flow in the order of the first gas inner channel 24, the through hole 25, and the first gas outer channel 4 as shown in FIG. . In addition, the first process gas can be supplied from the first gas supply port 5 to the vicinity of the outer periphery of the processing surface 101 of the workpiece 100 described later. As a result, a shield with the first process gas can be formed in the vicinity of the outer periphery of the surface to be processed 101, and therefore, the outside air can be prevented from flowing into the plasma generation region. Processing becomes possible.

  As shown in FIG. 3, the first gas supply port 5 of the present embodiment is continuous in an annular shape along the outer peripheral portion of the bottom portion 21 in a bottom view. According to such a configuration, the above-described effects due to the first process gas can be improved.

  Here, as shown in FIG. 2, the electrode portion 2 of the present embodiment described above includes a second gas flow channel 26 that is positioned in the hollow portion 23 so as to be partitioned from the first gas inner flow channel 24, and a bottom portion. And at least one second gas supply port 27 located at 21. The second gas channel 26 is a portion through which the second process gas flows. The second gas supply port 27 is connected to the second gas flow path 26 and penetrates between the upper surface 21 a and the lower surface 21 b of the bottom portion 21. According to such a configuration, the second process gas can be directly supplied from the second gas supply port 27 to the surface 101 to be processed, and therefore the generation efficiency of radicals as reactive species can be improved. It becomes possible to process the processing surface 101 efficiently by the atmospheric pressure plasma. As the second process gas, the same gas as exemplified in the first process gas described above can be used.

  The electrode unit 2 of the present embodiment has a plurality of second gas supply ports 27. As shown in FIG. 3, each of the plurality of second gas supply ports 27 is circular in a bottom view, and its diameter is sufficiently smaller than the diameter of the lower surface 21 b of the bottom portion 21. And the 2nd gas supply port 27 of this embodiment is arrange | positioned so that it may be located in the cross | intersection part of the virtual diagonal lattice element. In other words, the plurality of second gas supply ports 27 of the present embodiment are arranged alternately. According to such a configuration, the plurality of second gas supply ports 27 can be arranged so as to be close to each other, and the flow rate of the second process gas supplied from the second gas supply ports 27 can be appropriately reduced. Can do. As a result, it is possible to suppress the disappearance of plasma due to the high flow rate of the second process gas, and it is possible to improve the radical generation efficiency. It should be noted that “densely packed” means that the distance between the second gas supply ports 27, 27 adjacent to each other is the same as the diameter of the second gas supply port 27 or larger than the diameter of the second gas supply port 27. It means to be small. In the present embodiment, in order to improve the density of the plurality of second gas supply ports, a description has been given using an example in which the plurality of second gas supply ports 27 are arranged alternately (in a staggered manner). The second gas supply ports 27 only need to be close to each other, and may be arranged in, for example, an orthogonal lattice shape or a radial shape.

  Moreover, since the area | region 211 in which the several 2nd gas supply port 27 is located in the bottom part 21 also functions as an electrode, according to the structure mentioned above, efficient gas supply is maintained, maintaining an electric field strength. Is possible. The shapes of the plurality of second gas supply ports 27 may be the same or different. Further, the number and shape of the second gas supply ports 27 are not particularly limited as long as the region 211 functions as an electrode. For example, the diameter of each of the plurality of second gas supply ports 27 is set to the bottom 21 and the surface to be processed. It is preferable that the distance to the distance 101 is 1/10 or less. Further, each of the plurality of second supply ports 27 may be formed in the region 211 so as to have a honeycomb structure. With such a configuration, it is possible to achieve both the supply of the second process gas and the function as an electrode in the same region while maintaining the strength of the region 211.

  The second gas supply port 27 of the present embodiment is located at the center of the bottom 21. Further, the outer edge 211a of the region 211 is located at the same position as the intersection line 28 between the upper surface 21a of the bottom 21 and the inner surface 22a of the side wall part 22 (lower side wall part 221) or on the inner side of the intersection line part 28. It is good to have. In the present embodiment, the position of the outer edge portion 211 a is the same as the position of the intersection line portion 28. In the present embodiment, the position of the outer edge portion 211 a is the same as the position of the line of intersection with the outer peripheral portion of the second gas channel 26. According to such a structure, while the intensity | strength of the electrode part 2 can be maintained with the outer peripheral part of the bottom part 21 in which the 2nd gas supply port 27 is not located, heat dissipation can be improved. In addition, although the amount of the second process gas supplied to the processing surface 101 positioned immediately below the outer peripheral portion of the bottom portion 21 is smaller than that of the processing surface 101 positioned immediately below the center portion of the bottom portion 21, Since the second gas supply port 27 is not located at the outer peripheral portion of the base 21, the electric field strength is higher than that of the central portion of the bottom 21, and therefore the radical generation efficiency can be improved. In addition, by supplying the first process gas from the first gas supply port 5 to the outer peripheral portion of the bottom portion 21, a part of the first process gas can be used for generating plasma. Thereby, also in the outer peripheral part of the bottom part 21, the production | generation efficiency of a radical is securable. Such an effect is particularly noticeable when the first process gas and the second process gas are the same, and the center of the region 211 and the center of the bottom 21 are aligned.

  As shown in FIG. 4, the second gas supply port 27 of the present embodiment has a diameter D that increases from the upper surface 21 a to the lower surface 21 b of the bottom portion 21. Thereby, the second process gas supplied from the second gas supply port 27 can be diffused, and the radical generation efficiency can be improved. In order to make the diameter D have the above-described relationship, for example, the second gas supply port 27 may be formed from the lower surface 21b side of the bottom portion 21.

  As shown in FIG. 2, the second gas flow path 26 of the present embodiment is a gas supply pipe 261 that extends through the hollow portion 23 toward the bottom portion 21. The gas supply pipe 261 of the present embodiment is in contact with the top surface 21 a of the bottom portion 21 at the tip. Further, the gas supply pipe 261 of the present embodiment is disposed so as to align with the tubular side wall 22 and the axis. The first gas inner flow path 24 is located between the outer surface 261 a of the gas supply pipe 261 and the inner surface 22 a of the side wall portion 22. According to such a configuration, the second gas flow path 26 can be partitioned from the first gas inner flow path 24 in the hollow portion 23, and both the flow paths can be configured as independent flow paths. The respective compositions and flow rates of the process gas and the second process gas can be controlled.

<Atmospheric pressure plasma generator>
Next, an atmospheric pressure plasma generation apparatus (hereinafter sometimes referred to as “apparatus”) according to an embodiment of the present invention will be described. As shown in FIG. 1, the atmospheric pressure plasma generation apparatus 10 of the present embodiment includes an electrode 1 according to the above-described embodiment, a support base 11 that is positioned below the electrode 1 and supports a workpiece 100, A counter electrode 12 positioned opposite to the electrode 1, a voltage applying unit 13, and a gas supply unit 14 are provided below the workpiece 100.

  The support 11 may have a suction unit that sucks the workpiece 100. As an adsorption | suction means, a vacuum chuck etc. are mentioned, for example.

  The counter electrode 12 of this embodiment is located inside the support base 11. In addition, the counter electrode 12 of the present embodiment is electrically connected to the electrode 1 through the first conducting wire 133 included in the voltage applying unit 13 and is grounded through the second conducting wire 134.

  The voltage applying means 13 applies a voltage between the electrode 1 and the counter electrode 12. The voltage application means 13 of the present embodiment includes a high frequency power supply 131, a matching device 132, a first conductive wire 133, and a second conductive wire 134.

  The gas supply means 14 supplies the first process gas to the first gas inner flow path 24 and supplies the second process gas to the second gas flow path 26. Examples of the gas supply means 14 include a gas cylinder.

  The gas supply means 14 may have a flow rate control means for controlling the flow rates of the first process gas and the second process gas. Thereby, the accuracy of the gas flow rate can be improved, and stable machining can be performed. Examples of the flow rate control means include a mass flow controller.

  The apparatus 10 may further include a moving unit that relatively moves the electrode 1 and the support base 11 in the x-axis direction, the y-axis direction, and the z-axis direction.

<Method for producing atmospheric plasma processed product>
Next, a method for manufacturing an atmospheric pressure plasma workpiece according to an embodiment of the present invention will be described taking as an example the case of using the atmospheric pressure plasma generation apparatus 10 according to the embodiment described above.

The manufacturing method of the atmospheric pressure plasma workpiece of this embodiment includes the following steps (a) to (c).
(A) A step of supplying the first process gas to the first gas inner flow path 24 and supplying the second process gas to the second gas flow path 26 by the gas supply means 14 as shown in FIG.
(B) The first process gas is supplied from the first gas supply port 5 to the vicinity of the outer periphery of the workpiece surface 101 of the workpiece 100 and the second process gas is supplied from the second gas supply port 27 to the workpiece surface 101. Process.
(C) A step of generating atmospheric pressure plasma by applying a voltage between the electrode 1 and the counter electrode 12 by the voltage applying means 13.

  Through each of the steps as described above, an atmospheric pressure plasma workpiece 110 in which the workpiece surface 101 is precisely machined is manufactured.

  In the step (a), the compositions of the first process gas and the second process gas may be the same or different. Similarly, the flow rates of the first process gas and the second process gas may be the same or different. As the respective compositions and flow rates of the first process gas and the second process gas, desired values can be adopted according to the workpiece 100 as long as atmospheric pressure plasma can be stably generated. That is, according to the present embodiment, since the respective compositions and flow rates of the first process gas and the second process gas can be controlled, the processing surface 101 can be processed efficiently and stably.

  In particular, in the step (b), the first process gas is supplied from the first gas supply port 5 to form a shield with the first process gas in the vicinity of the outer periphery of the processing surface 101. It is possible to suppress the outside air from flowing in, and local processing using atmospheric pressure plasma becomes possible. Furthermore, since the generation efficiency of radicals as reactive species is improved by directly supplying the second process gas from the second gas supply port 27 to the processing surface 101, the processing surface 101 is efficiently formed by atmospheric pressure plasma. It becomes possible to process. The first process gas functions not only for the shield formation described above but also for plasma generation. From the above, it is preferable that the first process gas is larger than the flow rate of the second process gas in order to block outside air.

  Examples of the workpiece 100 used in the step (b) include glass such as quartz glass and alkali-free glass; crystalline material such as quartz; ceramics such as alumina, silica and titania; semiconductor materials such as silicon and silicon carbide. Resin materials such as polyethylene, polystyrene, polycarbonate and polyethylene terephthalate; GaN; AlN and the like.

  In the step (c), the applied power applied between the electrode 1 and the counter electrode 12 by the voltage applying means 13 is not particularly limited as long as atmospheric pressure plasma can be generated.

  As mentioned above, although several embodiment which concerns on this invention was described, this invention is not limited to the above-mentioned embodiment, It cannot be overemphasized that many corrections and changes can be added within the scope of the present invention. Yes.

  For example, in the above-described embodiment, the electrode unit 2 includes the plurality of second gas supply ports 27. Alternatively, the number of the second gas supply ports 27 may be one. Here, as the diameter of the second gas supply port 27 increases, the flow rate of the gas supplied from the second gas supply port 27 also increases. When the gas flow rate increases, the plasma may disappear. Therefore, when the number of the second gas supply ports 27 is one, the diameter of the second gas supply ports 27 is preferably set to a size that can suppress the disappearance of plasma. Specifically, the diameter of the second gas supply port 27 may be configured to be 1/10 or less with respect to the distance between the bottom portion 21 and the processing surface 101. The diameter of the second gas supply port 27 is preferably configured to be 1/10 or less with respect to the inner diameter of the gas supply pipe 261.

  In addition, the second gas supply hole 27 may have a single hole on the upper surface 21a of the bottom portion 21 and may branch to reach the lower surface 21b and have a plurality of holes on the lower surface 21b.

  Further, instead of the configuration of the above-described embodiment, the electrode 1 may further include a suction unit that sucks the vicinity of the plasma generation region. Thereby, excess radicals can be removed by suction, and the occurrence of processing defects due to the diffusion of excess radicals can be suppressed. Specifically, the electrode 1 further includes a cover that covers the outer surface of the tubular body 3 and has an exhaust port. And the suction means which exhausts with the pump for vacuum exhausts from an exhaust port is formed. Next, an atmospheric pressure plasma generation electrode according to another embodiment of the present invention having such suction means will be described in detail with reference to FIG. In FIG. 5, the same components as those in FIGS. 1 to 4 described above may be denoted by the same reference numerals and description thereof may be omitted.

  As shown in FIG. 5, the electrode 1 of this embodiment includes a cover 6 that surrounds the outer surface 3 b of the tubular body 3 with an inner surface 6 a through an exhaust gap 61, a tubular body 3, and a lower end portion 62 of the cover 6. At least one suction port 7 located between them, an exhaust passage 8 located in the exhaust gap 61 and connected to at least one suction port 7, and an exhaust passage located in the cover 6 8 further includes at least one exhaust port 9 connected to 8 and exhaust means (not shown) connected to the at least one exhaust port 9. According to these configurations, it is possible to locally exhaust the vicinity of the plasma generation region.

The electrode 1 of this embodiment having such a configuration can be suitably used in the following cases. For example, when silicon (Si) is used as the workpiece 100, if atmospheric pressure plasma is generated and processed, exhaust gas containing SiF ₄ or the like as a main component drifts around the processing surface 101, so that Si reattaches. May occur, and the film thickness distribution or arithmetic average roughness (Ra) may deteriorate. In addition, the exhaust gas described above may corrode metal parts of the device 10 and reduce the reliability of the device 10. Furthermore, radicals generated by atmospheric pressure plasma may drift around the processing surface 101, and etching may occur at locations other than the target, resulting in a deterioration in film thickness distribution. These problems are usually dealt with by surrounding the entire unit including the support base 11 with a casing and sucking and exhausting from the end of the casing, but the casing exhaust is insufficient. There is. In such a case, it is preferable to use the electrode 1 of the present embodiment that can be locally exhausted using the cover 6.

  The cover 6 of this embodiment is preferably made of an insulating material. Thereby, generation | occurrence | production of the plasma which is not intended between the to-be-processed surface 101 and the cover 6 can be suppressed. That is, since the cover 6 of this embodiment is disposed at a position close to the electrode portion 2 that generates discharge, it is preferable that the cover 6 be made of an insulating material from the viewpoint of suppressing unnecessary discharge and unintended electric field generation.

  Examples of the insulating material include ceramics such as alumina and aluminum nitride; sapphire and the like. An insulating material having a low thermal conductivity is preferable. That is, in the plasma local processing, the temperature of the workpiece 100 increases as the processing time increases, and the electrode 1 receives heat radiation from the workpiece 100. In order to make the conditions of the electrode 1 constant, the cover 6 is preferably made of a material having low thermal conductivity. Further, at the position where the cover 6 is arranged, the ambient temperature rises due to radiant heat from the workpiece 100 or the like. In order to fix the relative positional relationship of the workpiece 100, the electrode part 2, and the tubular body 3 irrespective of such temperature changes, the cover 6 is made of a material having a low thermal expansion coefficient and a low elastic modulus. It is good to do. The cover 6 is preferably made of a material that is difficult to be etched by plasma. In order to deal with these physical properties, the cover 6 is preferably made of the insulating material exemplified above.

  The position of the cover 6 is preferably close to the tubular body 3. Further, the position of the cover 6 is preferably a position where the suction port 7 can suck at a rate equal to or higher than the supply amount of the first and second process gases.

  In particular, the position of the cover 6 is such that the lower end 62 is located below the at least one through hole 25 of the electrode part 2 and is the same position as the lower end 33 of the tubular body 3 or the tubular body 3. It is good to be located above the lower end part 33. According to such a configuration, the vicinity of the plasma generation region can be locally evacuated while the function of the electrode 1 is reliably exhibited. That is, when the lower end portion 62 of the cover 6 is positioned below the through hole 25 of the electrode portion 2, it is possible to suppress the lower end portion 62 of the cover 6 from being too far from the bottom portion 21 of the electrode portion 2. When the lower end 62 of the cover 6 is located at the same position as or above the lower end 33 of the tubular body 3, a micro chamber is formed by the first process gas supplied from the first gas supply port 5. The function of the tubular body 3 described above can be exhibited. Therefore, according to the above-described configuration, local exhaust in the vicinity of the plasma generation region can be performed while the function of the electrode 1 is reliably exhibited.

  The lower end 62 of the cover 6 of the present embodiment is located above the lower end 33 of the tubular body 3. According to such a configuration, the following effects can be obtained. That is, in the plasma local processing, as described above, the temperature of the workpiece 100 increases as the processing time increases, and the electrode 1 receives heat from the workpiece 100. In order to precisely control the processing rate, it is necessary to know the temperature of the electrode 1. When the lower end portion 62 of the cover 6 is positioned above the lower end portion 33 of the tubular body 3, a part of the tubular body 3 is exposed, so that a radiation thermometer or spectroscopic measurement is possible. Further, by analyzing the emission wavelength of plasma, it is possible to make a relative comparison of excitation intensity and to identify the element being excited. Furthermore, the addition of a target element such as argon enables indirect radical density measurement by the actinometry method.

On the other hand, the shape of the suction port 7 is preferably the same as the shape of the first gas supply port 5. In the present embodiment, since the first gas supply port 5 continues in an annular shape along the outer peripheral portion of the bottom portion 21, the suction port 7 continues in an annular shape along the outer surface 3 b of the tubular body 3. Examples of the exhaust means include a vacuum exhaust pump.
Other configurations are the same as those of the electrode 1 according to the above-described embodiment, and thus the description thereof is omitted.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.

  The workpiece 100 was processed using the electrode 1 and the apparatus 10 according to the embodiment described above. Specific configurations of the electrode 1 and the apparatus 10 used are as follows.

<Configuration of Electrode 1 and Device 10>
Electrode portion 2: Aluminum tubular body 3: Alumina Diameter of bottom surface 21b of bottom portion 21: 3 mm
Diameter of second gas supply port 27: 56 μm
Other configurations are as shown in FIGS. 1 to 4 described above.

As the first process gas and the second process gas, a mixed gas of He, CF ₄ and O ₂ was used. This mixed gas was supplied to the workpiece 100 from the first gas supply port 5 and the second gas supply port 27 at the gas flow rates shown in Table 1. The unit of the gas flow rate in Table 1 is sccm (standard cubic centimeter per minutes = mm ³ / min).

The processing conditions of the workpiece 100 are as follows.
<Processing conditions>
Workpiece 100: Silicon (Si)
Applied power: 120W
Processing time: 60 seconds Distance between the bottom 21 and the processing surface 101: 300 μm

  The gas utilization efficiency and the processing rate when the workpiece 100 was processed under the above-described processing conditions were evaluated. Each evaluation method is shown below, and the results are shown in Table 1.

<Evaluation method of gas utilization efficiency>
Silicon (Si), which is the workpiece 100, is gasified and removed in the process of the reaction formula (A) shown below. In the reaction formula (A), the process (a) is the ionization of CF ₄ by He plasma and the oxidation process of Si.

[Reaction Formula (A)]

A concave processing mark is formed on the processing surface 101 of the workpiece 100 after a processing time of 60 seconds. The Si removal volume (mm ³ ) is measured from the concave processing trace, and the number of moles of evaporated Si per 60 seconds, that is, the number of moles of Si removed per 60 seconds is calculated. Further, the gas flow rate per 60 seconds CF _4, calculates the CF ₄ feed moles per 60 seconds. Then, the gas utilization efficiency (%) was calculated by applying the calculated value to the formula: (number of moles of Si removed per 60 seconds) / (number of moles of CF ₄ supplied per 60 seconds).

<Processing rate evaluation method>
The processing rate (mm ³ / sec) was calculated from the Si removal volume (mm ³ ) at the gas utilization efficiency described above. Further, the processing rate (%) when the processing rate (mm ³ / sec) of Comparative Example 1 described later is 100% is expressed by the formula: {[processing rate of Example 1 (mm ³ / sec)] / [Comparison The processing rate of Example 1 (mm ³ / sec)]} × 100.

  The applied power under the processing conditions was set to 135 W instead of 120 W, and the same electrode 1 and apparatus 10 as in Example 1 were used, except that the distance between the bottom 21 and the surface 101 to be processed was 500 μm. In the same manner, gas utilization efficiency and processing rate were evaluated. The results are shown in Table 1.

[Comparative Example 1]
An electrode and an apparatus having the same configuration as in Example 1 were used except that the electrode part did not have the second gas flow path 26 and the second gas supply port 27. Then, the gas utilization efficiency and the processing rate were evaluated in the same manner as in Example 1 except that the gas flow rate was changed to the value shown in Table 1 and the applied power of the processing conditions was changed to 100 W instead of 120 W. The results are shown in Table 1.

  As is apparent from Table 1, the electrode 1 of Examples 1 and 2 has significantly higher gas utilization efficiency and processing rate results than the electrode of Comparative Example 1, and can efficiently process the surface to be processed by atmospheric pressure plasma. I can see that

  In addition, as a result of confirming the machining traces of Examples 1 and 2, the machining amount does not decrease in the region 211 of the bottom portion 21 where the second gas supply holes 27 are formed, and is parabolic in a sectional view in the thickness direction. It was confirmed that the processing traces were made. This also confirmed that the electric field strength can be maintained on average in the region 211 of the bottom 21 regardless of the presence of the second gas supply hole 27.

  The state of the work surface 101 when the local exhaust was performed using the cover 6 was evaluated. First, the cover 6 shown in FIG. The specific configuration of the cover 6 used is as follows.

<Configuration of cover 6>
Cover 6: Made of alumina Position of the lower end portion 62 of the cover 6: Below the through hole 25 of the electrode portion 2 and above the lower end portion 33 of the tubular body 3 Other configurations are as shown in FIG. is there.

  Further, as the suction means connected to the exhaust port 9 of the cover 6, the first vacuum exhaust pump was used. In addition, a casing surrounding the entire unit including the support base 11 was used, and a second vacuum exhaust pump was connected to the end of the casing so that the casing could be exhausted.

As the first process gas and the second process gas, a mixed gas of He, CF ₄ and O ₂ was used. This mixed gas was supplied to the workpiece 100 from the first gas supply port 5 and the second gas supply port 27 at the same gas flow rate as in Example 1.

  And the to-be-processed material 100 was processed like Example 1 using the same electrode 1 and apparatus 10 as Example 1 except performing local exhaust and housing | casing exhaust. The local exhaust was performed by setting the suction condition of the first vacuum exhaust pump to 10 slm.

  As a result, there was no etched portion other than the target, and the desired processed surface 101 could be processed. In addition, as a result of performing only the case exhaust without attaching the cover 6 to the electrode 1, the portions other than the target were slightly etched. From these results, it can be seen that when the gas discharged from the electrode 1 and by-products generated during processing become a problem, it is preferable to use the cover 6 to perform local exhaust.

DESCRIPTION OF SYMBOLS 1 Electrode for atmospheric pressure plasma generation 2 Electrode part 21 Bottom part 21a Upper surface 21b Lower surface 211 Area 22 Side wall part 22a Inner surface 22b Outer surface 221 Lower side wall part 222 Upper side wall part 223 Step part 223a Locking part 23 Hollow part 24 1st gas inner channel 25 through-hole 26 second gas flow path 261 gas supply pipe 261a outer surface 27 second gas supply port 28 intersection part 3 tubular body 31 clearance 32 upper end part 33 lower end part 3a inner surface 3b outer surface 4 first gas outer flow path 5 first Gas supply port 6 Cover 61 Exhaust clearance 62 Lower end 6a Inner surface 7 Suction port 8 Exhaust flow path 9 Exhaust port 10 Atmospheric pressure plasma generator 11 Support base 12 Counter electrode 13 Voltage application means 131 High-frequency power supply 132 Matching device 133 First conductor 134 Second conductive wire 14 Gas supply means 100 Work material 101 Work surface 110 Atmospheric pressure Plasma workpiece

Claims (16)

A plate-like bottom portion having an upper surface and a lower surface, a tubular side wall portion connected to the outer peripheral portion of the bottom portion and extending upward, a hollow portion surrounded by an upper surface of the bottom portion and an inner surface of the side wall portion, the hollow portion A first gas inner flow path through which the first process gas flows, and an electrode section having at least one through hole located in the side wall and connected to the first gas inner flow path;
A tubular body that surrounds the outer surface of the side wall at the inner surface through a gap;
A first gas outer channel located in the gap and connected to the at least one through hole;
And at least one first gas supply port located between the bottom and the lower end of the tubular body and connected to the first gas outer channel,
The electrode part is located in the hollow part so as to be partitioned from the first gas inner flow path, and the second gas flow path through which the second process gas flows, and the second gas flow is located at the bottom part. An atmospheric pressure plasma generating electrode further comprising at least one second gas supply port connected to the path.   The electrode for generating atmospheric pressure plasma according to claim 1, wherein the electrode section has a plurality of the second gas supply ports.   The said 2nd gas supply port is an electrode for atmospheric pressure plasma generation | occurrence | production of Claim 2 arrange | positioned in the intersection of a virtual diagonal lattice.   The said at least 1 2nd gas supply port is an electrode for atmospheric pressure plasma generation in any one of Claims 1-3 located in the center part of the said bottom part.   The outer edge of the region where the at least one second gas supply port is located in the bottom is at the same position as the intersection between the upper surface of the bottom and the inner surface of the side wall, or from the intersection The electrode for generating atmospheric pressure plasma according to claim 1, which is also located inside.   6. The atmospheric pressure plasma generation electrode according to claim 1, wherein a diameter of the at least one second gas supply port increases from an upper surface to a lower surface of the bottom portion. The second gas flow path is a gas supply pipe extending through the hollow portion toward the bottom;
The said 1st gas inner side flow path is an electrode for atmospheric pressure plasma generation in any one of Claims 1-6 located between the outer surface of the said gas supply pipe, and the inner surface of the said side wall part.   The electrode part has a plurality of the through holes, and the plurality of through holes are positioned at substantially equal intervals along the outer peripheral direction at the same height. Electrode for atmospheric pressure plasma generation.   The said 1st gas supply port is an electrode for atmospheric pressure plasma generation in any one of Claims 1-8 which are continuing cyclically | annularly along the outer peripheral part of the said bottom part.   The said lower end part of the said tubular body is an electrode for atmospheric pressure plasma generation in any one of Claims 1-9 located below rather than the said bottom part of the said electrode part.   The electrode for generating atmospheric pressure plasma according to claim 1, wherein the tubular body is made of an insulating material. A cover made of an insulating material surrounding the outer surface of the tubular body on the inner surface through an exhaust gap;
At least one suction port located between the tubular body and the lower end of the cover;
An exhaust passage located in the exhaust gap and connected to the at least one suction port;
At least one exhaust port located in the cover and connected to the exhaust flow path;
The atmospheric pressure plasma generation electrode according to claim 1, further comprising an exhaust unit connected to the at least one exhaust port.   The lower end portion of the cover is positioned below the at least one through hole of the electrode portion, and is at the same position as the lower end portion of the tubular body or than the lower end portion of the tubular body. The electrode for generating atmospheric pressure plasma according to claim 12, which is located above. An electrode for generating atmospheric pressure plasma according to any one of claims 1 to 13,
A support base that is positioned below the atmospheric pressure plasma generating electrode and supports a workpiece;
A counter electrode positioned opposite to the atmospheric pressure plasma generating electrode below the workpiece;
Voltage applying means for applying a voltage between the atmospheric pressure plasma generating electrode and the counter electrode;
An atmospheric pressure plasma generator comprising gas supply means for supplying the first process gas to the first gas inner flow path and supplying the second process gas to the second gas flow path.   The atmospheric pressure plasma generation apparatus according to claim 14, wherein the gas supply means includes flow rate control means for controlling flow rates of the first process gas and the second process gas. A method for producing an atmospheric pressure plasma workpiece using the atmospheric pressure plasma generator according to claim 14, comprising:
Supplying the first process gas to the first gas inner flow path and supplying the second process gas to the second gas flow path by the gas supply means;
The first process gas is supplied from the at least one first gas supply port to the vicinity of the outer periphery of the work surface of the workpiece, and the second process gas is supplied from the at least one second gas supply port. Supplying the processed surface;
A method for producing an atmospheric pressure plasma workpiece, comprising: applying a voltage between the atmospheric pressure plasma generating electrode and the counter electrode by the voltage applying means to generate atmospheric pressure plasma.

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