Plasma gun and plasma processing device

Abstract

To provide a new suction type plasma gun with excellent processing reproducibility.SOLUTION: A plasma gun includes a suction end for sucking process gas, a capillary tube having an exhaust end connected to an exhaust device, an electrode arranged to surround the outer periphery of the capillary tube and connected to a high frequency power source, a gas supply portion having a supply hole for supplying the process gas from the outside of the capillary tube toward the suction end, and a partition portion that partitions at least the suction end and the supply hole with respect to the electrode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plasma gun and a plasma processing apparatus. [Background technology]

[0002] A plasma gun is known that excites a process gas flowing inside an insulating thin tube into plasma and supplies the plasma to a desired area on the surface of a workpiece. A method for processing a workpiece using the plasma gun and a plasma processing apparatus for the same are also known.

[0003] Local plasma, which processes desired areas of a workpiece, generally has a high plasma density and enables high-speed processing, so it is used for deep engraving of flat workpieces such as semiconductor wafers and planarization processes to eliminate waviness. In particular, suction plasma has attracted attention because it enables high-speed processing and produces clean processed surfaces, and further applications are expected.

[0004] As an example of a plasma processing apparatus (plasma etching apparatus) having such a suction type plasma gun, Patent Document 1 describes the following: "An suction type plasma etching apparatus comprising a sealed container having a sample stage inside the container and a gas inlet portion, a capillary, and a plasma gun having a plasma generation electrode surrounding the capillary, wherein at least the tip of the capillary is disposed within the sealed container and is configured to face an object to be etched placed on the sample stage, the rear end of the capillary is connected to an exhaust device installed outside the sealed container, and a reaction raw material gas introduced into the sealed container from the gas inlet portion is sucked in from the opening at the tip of the capillary." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-153783 A Summary of the Invention [Problem to be solved by the invention]

[0006] The plasma processing device incorporating the suction-type plasma gun described in Patent Document 1 has excellent features, such as being capable of high-speed processing and being able to obtain clean processed surfaces that are unique to the suction type. On the other hand, the inventors have found that, depending on the processing conditions, etc., variation occurs in the degree of processing; in other words, there is room for improvement in terms of processing reproducibility.

[0007] Therefore, an object of the present invention is to provide a novel suction-type plasma gun having excellent processing reproducibility, and a plasma processing apparatus having the plasma gun. [Means for solving the problem]

[0008] As a result of intensive research by the present inventors to solve the above problems, they have found that the above problems can be solved by the following configuration.

[0009] [1] A capillary tube having an intake end for intake of a process gas and an exhaust end connected to an exhaust device, an electrode arranged to surround the outer periphery of the capillary tube and connected to a high frequency power source, and a gas supply unit having a supply hole for supplying the process gas from the outside of the capillary tube toward the intake end; A plasma gun comprising at least the suction end and a partition portion that (air-tightly) separates the supply hole from the electrode. [2] The plasma gun described in [1], further comprising a guide for suppressing diffusion of the process gas. [3] The plasma gun described in [2], wherein the suction end, the supply hole, and the guide are arranged in a substantially concentric shape in this order from the center, with the suction end at the center. [4] When the distance from the center of the suction end to the supply hole is D meters and the flow rate of the process gas supplied from the supply hole is V meters per second, D / V is 4.0×10 -1 1. A plasma gun as described in [1] below. [5] The plasma gun according to [3], wherein the guide is arranged to surround the outer periphery of the capillary tube. [6] A plasma gun described in any one of [2] to [3] or [5], wherein the suction end protrudes along an axial direction from the exhaust end to the suction end compared to the supply hole and the tip of the guide. [7] A plasma gun described in any of [2] to [3] or [5], further comprising a shower plate provided across the guide and the capillary tube, covering the supply hole and separating the suction end and the supply hole, the shower plate having through holes for allowing the process gas to pass to the suction end side. [8] The plasma gun described in [6], wherein the gas supply section includes a tubular member wound around the outer periphery of the capillary tube, and a plurality of the supply holes are arranged in a body of the tubular member. [9] The plasma gun described in [6], wherein the electrode is placed in an atmospheric pressure environment, and plasma processing of the workpiece is performed by plasma generated near the suction end while flowing counter to the gas flow of the process gas flowing from the suction end adjacent to the workpiece under reduced pressure toward the exhaust end.

[10] A plasma processing apparatus comprising the plasma gun described in [1] and a reduced pressure chamber for accommodating a workpiece, wherein the plasma gun and the reduced pressure chamber are airtightly connected so that at least the suction end and the supply hole are positioned within the reduced pressure chamber.

[11] The plasma processing apparatus described in

[10] , wherein the electrode is placed in an atmospheric pressure environment, and plasma processing of the workpiece is performed by plasma generated near the suction end while flowing counter to the gas flow of the process gas flowing from the suction end adjacent to the workpiece under reduced pressure toward the exhaust end. Effect of the Invention

[0010] According to the present invention, there is provided a novel suction-type plasma gun having excellent processing reproducibility, and also a plasma processing apparatus having the plasma gun. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram for explaining the structure of one embodiment of a plasma gun of the present invention. [Diagram 2] FIG. 13 is an explanatory diagram of a modified example of the plasma gun of the present invention. [Diagram 3] 1 is a partial cross-sectional view of a plasma processing apparatus having a plasma gun according to the present invention. [Figure 4] 1 is a graph showing the relationship between the pressure waiting time from the introduction of the process gas until the start of processing and the etching rate in a plasma processing device (conventional device). [Diagram 5] 1 is a graph showing the relationship between the etching rate and the "pressure waiting time" from the introduction of the process gas to the start of processing in the plasma processing device (plasma processing device of the present invention). [Figure 6] 5A to 5C are schematic diagrams for explaining the structure of another embodiment of the plasma gun of the present invention. [Figure 7] 5A to 5C are schematic diagrams for explaining the structure of another embodiment of the plasma gun of the present invention. [Figure 8] 1 is a partial cross-sectional view of a plasma processing apparatus having a reduced pressure chamber and a conventional suction type plasma gun. [Figure 9] 1 is a schematic diagram of a plasma processing apparatus equipped with a plasma gun of the present invention. [Figure 10] The results are obtained by changing the distance c between the axis of the capillary tube 10 and the axis of the gas supply unit 13B (13A) and investigating the reproducibility (processing reproducibility) and the processing rate (etching rate). [Figure 11] The distance b between the axis of the capillary tube 10 and the tip of the guide 16 was changed, and the reproducibility (processing reproducibility) and processing rate (etching rate) were investigated. [Figure 12]FIG. 11 is a schematic diagram for explaining the structure of a plasma gun (embodiment 5) according to the present invention. [Figure 13] FIG. 11 is a partial cross-sectional view of a plasma processing apparatus having a plasma gun (embodiment 5) according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0013] The embodiment shown below is an example that embodies the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the material, shape, structure, arrangement, etc. of the components to the embodiment shown below. The drawings are schematic. Therefore, the relationship and ratio between the thickness and the planar dimensions may differ from the actual ones, and the relationship and ratio of the dimensions may differ between the drawings.

[0014] [Example 1] An embodiment of the plasma gun of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram for explaining the structure of one embodiment of the plasma gun of the present invention. Fig. 1(a) is a cross-sectional view taken along line AA, Fig. 1(b) is a bottom view, and Fig. 1(c) is a bottom view with a shower head, which will be described later, removed. In the following description, as shown in each coordinate axis in FIG. 1, the + (plus) direction of the Z axis will be referred to as the "Z (+) direction" and the - (minus) direction will be referred to as the "Z (-) direction", and the same applies to the X and Y axes.

[0015] The plasma gun 100 comprises a capillary tube 10, an electrode 20 arranged to surround its outer circumference, gas supply units 13A, 13B having supply holes 14A, 14B for supplying a process gas toward the suction end 11 of the capillary tube 10, and a partition unit 15 that separates the suction end 11, the supply hole 14A, and the supply hole 14B from the electrode 20. Furthermore, a cylindrical guide 16 is disposed on the outer periphery of gas supply parts 13A and 13B. A shower plate 17 is disposed at the tip (the end in the Z (-) direction) of guide 16. Shower plate 17 is provided from the tip of guide 16 to the outer periphery of capillary tube 10, and is provided so as to cover supply holes 14A and 14B.

[0016] Capillary tube 10 is a hollow tubular member having openings at both ends, and process gas is sucked in from one end, suction end 11, and this process gas flows inside capillary tube 10 and is exhausted from the other end, exhaust end 12. When plasma gun 100 is applied to a plasma processing device (described later), exhaust end 12 is connected to an exhaust module (exhaust device), and the gas flow is formed by the exhaust module.

[0017] The diameter of the capillary tube 10 is not particularly limited, but the hole diameter of the suction end 11, i.e., the diameter of the end close to the workpiece, may be appropriately selected depending on the size of the area to be processed. As an embodiment, the hole diameter of the suction end 11 is preferably 0.1 to 5.0 mm. As an embodiment, the length is not particularly limited, but as an embodiment, the hole diameter is preferably 50 to 500 mm. As an embodiment, the thickness is not particularly limited, but as an embodiment, the hole diameter is preferably 1 to 10 mm. Furthermore, the material of the capillary tube 10 is not particularly limited, but a material capable of dielectric barrier discharge is preferable, for example, inorganic insulators such as quartz glass and alumina ceramics; resins such as PTFE (polytetrafluoroethylene); etc.

[0018] 1(a), (b), and (c), the capillary tube 10 is cylindrical with both ends having approximately the same diameter, but the shape of the capillary tube applicable to the plasma gun of the present invention is not limited to the above. For example, the capillary tube may have a smaller diameter at the suction end 11 than at the exhaust end 12, and may have a so-called tapered shape with a "constriction" at the body. It may also have a shape in which the hole diameter narrows and converges in a tapered shape. It may also have a shape opposite to the above, in which the exhaust end 12 side is narrowed. The shape of the capillary tube 10, the hole diameter of the suction end 11, and the ratio of the hole diameters at both ends may be appropriately adjusted depending on the size of the target processing area, etc.

[0019] The electrode 20 is connected to a high-frequency power supply. The high-frequency electromagnetic field induced by the high-frequency power applied to the electrode 20 excites the plasma gas in the capillary tube 10. At this time, since the gas flow of the process gas is in the axial direction (Z(+) direction) from the suction end 11 to the exhaust end 12, the generated plasma remains in the vicinity of the suction end 11 without being sprayed outward so as to diffuse from the suction end 11. In this specification, this state is sometimes referred to as "plasma generated in the vicinity of the suction end."

[0020] The position of electrode 20 relative to capillary tube 10 is not particularly limited, but the distance from suction end 11 to electrode 20 is preferably 0.5 times or more, and more preferably 0.8 times or more, the diameter of capillary tube 10. There is no particular upper limit, but in one embodiment, it is preferably 10 times or less.

[0021] The material of the electrode 20 is not particularly limited, but is preferably copper, phosphor bronze, or the like, which has excellent electrical conductivity, or stainless steel, or the like, which has excellent corrosion resistance. In Fig. 1, the electrode 20 is cylindrical and surrounds the outer periphery of the capillary tube 10, but may be in a coil shape or the like other than the above, and the shape is not particularly limited.

[0022] The electrode 20 is connected to a high-frequency power source. The high-frequency power source is not particularly limited as long as it can generate a high-frequency electromagnetic field inside the capillary tube 10, and a known power source device equipped with switching elements such as a transistor and a vacuum tube can be used. The frequency is not particularly limited, but is preferably 3 to 30 MHz, and for plasma excitation, a power source device that generates an AC electromagnetic field with a frequency of 13.56 MHz is often used.

[0023] During use, the electrode 20 is preferably placed in an atmospheric pressure environment or an atmosphere close to atmospheric pressure, and is preferably placed in an atmospheric pressure environment. By placing the electrode 20 in an atmospheric pressure environment, unintended discharge from the electrode 20 can be suppressed. On the other hand, when the plasma gun 100 is in use, the suction end 11 of the capillary tube 10 and the supply holes 14A and 14B need to be close to the workpiece under reduced pressure or be placed in the same atmosphere. The plasma gun 100 has a partition 15 for separating the portion to be placed under atmospheric pressure from the portion to be placed under reduced pressure.

[0024] Partition 15 has the function of separating suction end 11 and supply holes 14A and 14B from electrode 20. Specifically, it is a substantially cylindrical member with a bottom that is provided from the body of cylindrical gas supply parts 13A and 13B to the body of capillary tube 10. A hole is provided in the bottom part, and capillary tube 10 is airtightly fitted into this part. Therefore, electrode 20 is airtightly separated from suction end 11, supply holes 14A, and supply holes 14B.

[0025] The material of partition 15 is not particularly limited, and may be any of inorganic materials such as metal, glass, other oxides and nitrides, and organic materials such as resin, or a combination of these. In one embodiment, the same material as capillary tube 10 may be used. The thickness is not particularly limited as long as it can connect and support capillary tube 10 and gas supply units 13A and 13B, and can maintain its shape even when one side (suction end 11 side) is depressurized, and may be appropriately selected taking into consideration the size of the member to be supported and the pressure difference between the two spaces to be partitioned, etc.

[0026] Because the plasma gun 100 has a partition portion 15, even if the electrode 20 is placed in an atmospheric pressure environment, it is easy to place the suction end 11, supply hole 14A, and supply hole 14B in the same atmosphere as the workpiece, which is under reduced pressure. The structure of partition 15 is not limited to the above as long as it can (airtightly) separate the suction end and the supply hole from the electrode. In particular, in plasma gun 100, partition 15 is made of one member, but it may be made of two or more members combined to function as partition 15.

[0027] Gas supply units 13A and 13B are disposed radially outside of capillary tube 10, and supply process gas from supply holes 14A, 14B toward suction end 11. "Toward suction end 11" means that a gas flow of the process gas can be formed in a direction from gas supply units 13A, 13B toward suction end 11. Gas supply units 13A and 13B are made of tubular members having openings at both ends, one of which serves as supply holes 14A and 14B, and the other of which is connected to a process gas supply module during use.

[0028] The hole diameter of gas supply parts 13A and 13B is not particularly limited. It may be adjusted appropriately depending on the supply amount and pressure of the process gas. For example, when plasma gun 100 is applied to a plasma processing apparatus described later, under general processing conditions, the pressure in reduced pressure chamber 33 may be adjusted to 100 to 5000 Pa, and the pressure in capillary tube 10 may be adjusted to 1 to 2000 Pa, and the adjustment may be made based on this. As one embodiment, a diameter of 0.1 to 5 mm is preferable.

[0029] The amount of gas (gas flow rate) supplied from gas supply units 13A and 13B may be determined by the difference (differential pressure) between the pressure in a decompression chamber described below in which plasma gun 100 is installed and the pressure in capillary tube 10. That is, the hole diameters of gas supply parts 13A and 13B can be determined based on the inner diameter of capillary tube 10, the exhaust capacity of the exhaust module connected thereto, and the capacity of the process gas supply module. The specific flow velocity (V [m / s]) of the process gas is not particularly limited, but is preferably 0.01 to 10 m / s, and more preferably 0.1 to 5.0 m / s. When there are multiple supply holes, the flow velocities of the process gases may be the same or different, but are preferably approximately the same.

[0030] The distance (D [m / s]) from the center of suction end 11 of capillary tube 10 to supply holes 14A and 14B is not particularly limited, but is preferably 10 mm to 200 mm, and more preferably 10 to 150 mm. When there are multiple supply holes, it is preferable that each distance D is within the above numerical range.

[0031] Here, the relationship between the distance from the center of the suction end to the (center of) the supply hole and the flow rate of the process gas supplied from the supply hole is not particularly limited, but from the viewpoint of shortening the time from the start of the supply of the process gas to the state in which stable processing can be started, it is preferable that the D / V is 1.0 or less, less than 1.0, 7.0×10 -1 Below, 7.0 x 10 -1 Less than 4.0×10 -1Below, 1.0 x 10 -1 Less than 7.0×10 -2 Below, 7.0 x 10 -2 Less than or equal to 4.0 x 10 -2 The lower limit is not particularly limited, but from the viewpoint of facilitating control of the flow rate of the supplied process gas, it is preferably 1.0×10 -3 That is, the D / V is preferably 1.0×10 or more in terms of shortening the time required from the start of supply of the process gas until a state in which stable processing can be started is reached and the process gas flow rate is easily controlled. -3 Greater than or equal to 1.0; 1.0×10 -3 Greater than or equal to 1.0, less than 1.0; 1.0 x 10 -3 That's it, 7.0 x 10 -1 Less than or equal to 1.0 x 10 -3 That's it, 7.0 x 10 -1 Less than 1.0 x 10 -3 That's it, 4.0 x 10 -1 Less than or equal to 1.0 x 10 -3 That's it, 1.0 x 10 -1 Less than 1.0 x 10 -3 That's it, 7.0 x 10 -2 Less than or equal to 1.0 x 10 -3 That's it, 7.0 x 10 -2 Less than 1.0 x 10 -3 That's it, 4.0 x 10 -2 The following is preferred: When there are a plurality of supply holes, it is preferable that the D / V of each of them is within the above numerical range.

[0032] In FIG. 1(c), gas supply units 13A and 13B are arranged with 180° rotational symmetry around suction end 11. However, the number of gas supply parts made of tubular members is not limited to two, and may be one, or three or more.

[0033] When the plasma gun 100 has multiple gas supply units, their arrangement is not particularly limited, but it is preferable that the gas supply units are arranged so that gas can be introduced approximately axially symmetrically near the central axis of the capillary tube 10. Specifically, when there are n gas supply units, the supply holes are preferably spaced apart from each other by about 360 / n degrees when viewed from the bottom, with suction end 11 as the center. That is, the n supply holes are preferably arranged with rotational symmetry of 360 / n degrees with suction end 11 as the center. By arranging the gas supply section as described above, the supply holes are arranged approximately axially symmetrically with respect to the suction end 11 of the capillary tube 10, resulting in a more uniform supply of process gas and achieving better effects of the present invention.

[0034] Further, gas supply parts 13A and 13B are configured by tubular members, but the material of this tubular member is not particularly limited, and the same material as that of partition part 15 already described can be used.

[0035] The process gas to be supplied may be appropriately selected depending on the material of the workpiece, etc. For example, when the material of the workpiece is silicon, silicon dioxide, etc., fluorocarbon gases such as SF6 and CF4 are often used as the process gas. In addition, O2, etc. may be added to the above gases.

[0036] Furthermore, the gas supply unit is not limited to being a cylindrical member (tubular member), and may be composed of a member of another shape. 2A and 2B are explanatory diagrams of a modified example of the plasma gun in which the shape of the gas supply part is different from that of Example 1. Fig. 2(a) is a cross-sectional view taken along line BB, and Fig. 2(b) is a bottom view thereof. In Fig. 2(b), in order to make the positions of the suction end 11 and the supply hole 14A easier to see, the other parts are shown shaded. Other bottom views also have colored parts for the same reason.

[0037] In the plasma gun 110, the gas supply section 13C has a double-tube structure consisting of an outer tube 40 and an inner tube 41, and the capillary tube 10 is disposed inside the inner tube 41, and the capillary tube 10, the inner tube 41, and the outer tube 40 are disposed in this order in a substantially concentric manner with the capillary tube 10 at the center. In the plasma gun 110, the gap (clearance) between the outer tube 40 and the inner tube 41 serves as a supply path for the process gas, and the process gas is discharged from the supply hole 14A, which is an opening at the tip of the gap. This generates a gas flow from the supply hole 14A toward the suction end 11.

[0038] In this modification, supply hole 14A is provided over the entire outer periphery of capillary tube 10 (so as to surround the entire circumference), but the shape of supply hole 14A is not limited to the above. For example, when gas supply section 13C has a shape obtained by dividing a double pipe into two or more in the axial direction, supply hole 14A may be arc-shaped. Furthermore, the plasma gun 110 does not have a shower plate 17, which will be described later, but it is preferable that the plasma gun 110 has one.

[0039] Returning to FIG. 1, the description of the configuration of the plasma gun 100 will continue. Guides 16 are arranged on the outer periphery of gas supply parts 13A and 13B to suppress diffusion of the process gas supplied from supply holes 14A and 14B. Guide 16 is made of a tubular member with a larger diameter than capillary tube 10 and partition part 15, and is arranged concentrically in bottom view so as to surround capillary tube 10 in the order of capillary tube 10, partition part 15, and guide 16.

[0040] The process gas flows through the gap defined by the partition 15 and the inner wall of the guide 16, and reaches the suction end 11 in a state where diffusion is more suppressed. When the plasma gun 100 has the guide 16, the processing device equipped with the plasma gun 100 has better processing reproducibility. Although the mechanism is not entirely clear, it is presumed that this is because the concentration distribution of the process gas in the vicinity of the plasma generation position can be made more uniform. This mechanism will be described in detail later. Because the plasma gun 100 has the guide 16, it has a superior effect of the present invention, as will be apparent from the results of the demonstration test described later. On the other hand, the plasma gun of the present invention does not have to have the guide 16. Even without the guide 16, the plasma gun has a sufficient effect for practical use.

[0041] In plasma gun 100, guide 16 is made of a tubular member and is provided so as to surround the entire outer periphery of capillary tube 10. In other words, it has a double-tube structure with capillary tube 10 as the inner tube and guide 16 as the outer tube. A plasma processing apparatus having plasma gun 100 configured in this way has better processing reproducibility. However, as long as the diffusion of the process gas can be suppressed, the structure of the guide 16 is not limited to the above. For example, the guide 16 may be arc-shaped when viewed from the bottom. That is, the guide 16 may have a divided structure with slits in the axial direction. The guide 16 may also be rectangular or polygonal, or may be elliptical. The guide 16 may also be polygonal, for example rectangular, when viewed from the bottom.

[0042] The guide 16 may also have a tapered portion. For example, it may have a constriction in the direction toward the suction end 11. It may also have a shape in which a large diameter portion and a small diameter portion are connected via a connecting portion that may have a taper, that is, a shape in which cylinders with different hole diameters are stacked. As described above, it is preferable that guide 16 has a tapered portion or has a shape in which cylinders with different hole diameters are stacked on top of each other, since this makes it possible to easily adjust the gas flows from gas supply portions 13A and 13B.

[0043] As is clear from FIG. 1(c), in the plasma gun 100, the suction end 11, the supply holes 14A, 14B, and the guide 16 (the tip in the Z(-) direction) are arranged in this order in a substantially concentric manner with the suction end 11 at the center when viewed from the bottom. With this arrangement, the diffusion of the process gas supplied from supply holes 14A, 14B is further suppressed, and the plasma processing apparatus having plasma gun 100 has even better processing reproducibility.

[0044] The positional relationship (upper and lower relationship) in the Z-axis direction of suction end 11 of capillary tube 10, the tip of guide 16, and supply holes 14A and 14B is not particularly limited, but it is preferable that, along the Z(-) direction, i.e., the axial direction of capillary tube 10 from exhaust end 12 to suction end 11, they are, in order from the Z(+) direction, supply holes 14A and 14B (position P3), the tip of guide 16 (position P2), and suction end 11 (position P1). That is, it is preferable that the position (P1) of the suction end 11 protrudes in the Z(-) direction compared to the other positions (P2, P3).

[0045] The plasma gun 100 is used by bringing the suction end 11, which generates plasma, close to the workpiece. Therefore, by having the suction end 11 protrude in the Z(-) direction from the above-mentioned parts, a greater variety of workpieces can be machined. Specifically, even when used for flattening a flat workpiece having a diameter larger than that of the guide 16, the suction end 11 protrudes in the Z(-) direction, so that the guide 16 (its tip) and the supply holes 14A and 14B tend to be prevented from interfering with the workpiece. As a result, larger workpieces can be machined.

[0046] 1(B), plasma gun 100 has a shower plate 17 that is provided from the tip of guide 16 to the outer periphery of capillary tube 10. Shower plate 17 is a disk-shaped member with a hole at approximately the center, into which capillary tube 10 is airtightly fitted. Shower plate 17 is disposed so as to partition and cover supply holes 14A and 14B from suction end 11.

[0047] The shower plate 17 is provided with a plurality of through holes 18 along the thickness direction from the front surface to the back surface. The process gas supplied from the supply holes 14A and 14B passes through the through holes 18 and is supplied to the suction end 11. The shower plate 17 makes it easier to supply the process gas more uniformly from a plurality of directions to the suction end 11, and as a result, a more excellent effect of the present invention can be obtained. The shower plate 17 only needs to have one through hole 18, and it is more preferable that the shower plate 17 has a plurality of through holes. In FIG. 1(B), the through holes 18 are arranged throughout the shower plate 17, but the present invention is not limited to the above, and may be arranged concentrated in the center, for example. The material of the shower plate 17 is not particularly limited, and may be, for example, ceramics.

[0048] Next, a method of applying the above-mentioned plasma gun to a plasma processing apparatus will be described.

[0049] The plasma processing apparatus 200 includes a decompression chamber 33 , a moving mechanism 36 installed in the decompression chamber 33 , a workpiece support table 35 arranged on the moving mechanism 36 , and a plasma gun 100 .

[0050] The plasma gun 100 is air-tightly connected to the reduced pressure chamber 33 such that the suction end 11 and supply holes 14A, 14B are inside the reduced pressure chamber 33 and the electrode 20 is outside the reduced pressure chamber 33. Specifically, a hole is provided in the reduced pressure chamber 33 along the outer periphery of the guide 16, and the plasma gun 100 is air-tightly fitted and fixed in the hole. At this time, the inside of the reduced pressure chamber 33 is divided from the outside of the reduced pressure chamber 33 by the partition part 15.

[0051] An exhaust module 30 is connected to the exhaust end 12 of the capillary tube 10, and a process gas supply module 31 is connected to the other ends (the ends opposite the supply holes 14A and 14B) of the tubular members of the gas supply units 13A and 13B. The exhaust module 30 reduces the pressure in the decompression chamber 33 through the capillary tube 10, and also draws in the process gas supplied from the process gas supply module 31 through the gas supply sections 13A and 13B into the decompression chamber 33 from the suction end 11 to form a gas flow.

[0052] That is, the process gas is supplied from the process gas supply module 31 to the gas supply sections 13A and 13B, flows from the supply holes 14A and 14B (gas flow F1), through the through holes 18 of the shower plate 17, into the decompression chamber 33 (gas flow F2), is sucked into the inside of the capillary tube 10 (gas flow F3), and is released through the exhaust module 30 (gas flow F4).

[0053] A high-frequency power supply 32 is connected to the electrode 20. With the workpiece 34 and the suction end 11 in close proximity to each other, the pressure inside the decompression chamber 33 is reduced by the exhaust module 30, and with a process gas being supplied, a high-frequency electromagnetic field is induced inside the capillary tube 10, whereby the process gas is excited into plasma inside the capillary tube 10. The generated plasma travels against the gas flow F3 and reaches the vicinity of the suction end 11, thereby processing the surface of the workpiece 34 placed (housed) in the decompression chamber 33. In addition, the shorter the distance (gap) between the workpiece and the suction end 11, the easier it is to limit the range of influence of the plasma and to perform more accurate machining. The size of the gap can be adjusted appropriately according to the hole diameter of the suction end 11, but as an example, when the hole diameter of the suction end 11 is 1 mm, the gap is preferably 1 mm or less, and more preferably 0.5 mm or less.

[0054] In a plasma processing device equipped with a suction type plasma gun, the generated plasma flows against the gas flow as described above, so it does not diffuse more than necessary from the suction end 11. This makes it easy to precisely narrow the processing area. Furthermore, since processing residues and the like are discharged and removed by the gas flow, a clean processing surface can be obtained. The above is one of the features of the suction type plasma gun.

[0055] The decompression chamber 33 may further have a chamber supply hole (not shown) for supplying a process gas. The process gas may be supplied to the chamber supply hole from the process gas supply module 31, or may be supplied from a process gas supply mechanism separate from the process gas supply module 31.

[0056] The chamber supply hole provided in the reduced pressure chamber 33 is used to replace the gas in the reduced pressure chamber 33 with the process gas. However, the plasma processing apparatus 200 does not have to have a chamber supply hole. Since the plasma processing apparatus 200 includes the plasma gun 100, it has excellent processing reproducibility even when the process gas replacement in the reduced pressure chamber 33 is not performed. The relationship between the process gas replacement in the reduced pressure chamber 33 and the processing reproducibility will be explained based on the results of a demonstration test described later.

[0057] The workpiece 34 is fixed on the workpiece support table 35. The workpiece support table 35 can be moved at least in the Z direction by a moving mechanism 36. The moving mechanism 36 is preferably capable of moving the workpiece 34 fixed to the workpiece support table 35 in the X direction and the Y direction, and may further rotate the workpiece 34 supported by the workpiece support table 35 around at least one axis selected from the group consisting of the Z axis, the X axis, and the Y axis.

[0058] In plasma processing apparatus 200, the relative position between suction end 11 and workpiece 34 is adjusted by moving workpiece 34, but a moving mechanism may also be provided on the plasma gun 100 side. Also, the workpiece 34 may be fixed, and only plasma gun 100 may move.

[0059] By using the plasma processing apparatus 200 configured as described above, excellent processing reproducibility can be obtained. Below, a demonstration experiment is explained, and an unexpected secondary effect obtained by using the plasma gun 100, which was revealed in the demonstration experiment, is also explained.

[0060] [Demonstration experiment] Below, a plasma processing apparatus equipped with plasma gun 100 is compared with a plasma processing apparatus equipped with a conventional suction-type plasma gun, and the results of a demonstration test verifying the excellent effects of this plasma processing apparatus are described in detail.

[0061] First, a conventional suction type plasma gun used for comparison and a plasma processing apparatus equipped with the same will be described. Fig. 8 is a partial cross-sectional view of a plasma processing apparatus 500 having a reduced pressure chamber 33 and a conventional suction type plasma gun. The plasma gun does not have a gas supply unit, and instead, a gas supply unit 50 is arranged in the reduced pressure chamber 33. An exhaust module 30 is connected to the exhaust end 12 of the capillary tube 10, a high-frequency power supply 32 is connected to the electrode 20, a process gas supply module 31 is connected to the gas supply unit 50, and the gas supply unit 50 is connected to the decompression chamber 33, and the configuration and function of each are similar to those of the plasma processing apparatus 200 in FIG. 3.

[0062] In the plasma processing apparatus 500, the pressure inside the reduced pressure chamber 33 is reduced by the exhaust module 30, and a process gas is supplied from the gas supply section 50 to the reduced pressure chamber 33 (gas flow F5), which is sucked into the capillary tube 10 from the suction end 11 (gas flow F3), and discharged outside the apparatus via the exhaust module 30 (gas flow F4).

[0063] The present inventors have found that processing reproducibility may decrease in plasma processing apparatus 500, and have thoroughly investigated the cause thereof. As a result, they have found that processing reproducibility is particularly likely to decrease immediately after processing begins, or as the volume of reduced pressure chamber 33 increases, and they have hypothesized that the gas composition in reduced pressure chamber 33 (i.e., the concentration distribution of the process gas) has an effect.

[0064] Before describing the relationship between the concentration distribution of the process gas and the processing reproducibility, a procedure for plasma processing using the plasma processing apparatus 500 will be briefly described. First, when starting plasma processing, a "purging" is performed to push impurities (gas) in the decompression chamber 33 out of the decompression chamber 33 with the process gas used in processing. "Purging" (hereinafter also referred to as "replacement") is performed, for example, by introducing a process gas at a predetermined pressure into the decompression chamber 33. Thereafter, gas is exhausted from the decompression chamber 33, and the pressure is reduced to a predetermined level. Then, the pressure is increased to the target pressure for processing while again introducing the process gas, and the chamber is placed on standby for a certain period of time (pressure standby time).

[0065] In the above procedure, the inventors first predicted that if the purging of the inside of the reduced pressure chamber 33 with the process gas is insufficient and the concentration distribution of the process gas is non-uniform, the processability will be reduced. Therefore, in order to investigate the effect of the replacement inside the decompression chamber 33 on the processing reproducibility, the processing reproducibility in the depth direction of the workpiece with and without replacement was compared.

[0066] As a result, the inventors obtained experimental results showing that the processing reproducibility is improved by replacing the inside of the reduced pressure chamber 33 with the process gas. From the above experimental results, the inventors considered that the desired processing reproducibility can be obtained if the inside of the reduced pressure chamber 33 can be sufficiently replaced with the process gas.

[0067] However, further experiments revealed that in conventional plasma processing apparatus 500, the desired processing reproducibility could not be obtained by simply replacing (purging) the process gas in the reduced pressure chamber. 4 is a graph showing the relationship between the etching rate and the "pressure waiting time" from the introduction of the process gas to the start of processing in a plasma processing device. The error bars indicate the variation in the etching rate.

[0068] From the results of Fig. 4, it was found that when the pressure standby time was between 0 and 20 minutes, the etching rate had a large variation (low processing reproducibility). It was also found that this variation decreased over time. In other words, it was thought that by increasing the pressure standby time, the process gas concentration in the decompression chamber 33 became more uniform, and as a result, the processing reproducibility improved (the variation decreased).

[0069] However, surprisingly, when one looks closely at Figure 4, it becomes clear that the etching rate drops significantly as the pressure standby time elapses. For example, the etching rate was about 9.7 μm / min after 5 minutes of pressure standby time, but after 30 minutes of pressure standby time, it dropped to about 9.1 μm / min, a drop of about 0.6 μm / min, or about 6.2%. Although Figure 4 only shows the pressure standby time up to 30 minutes, the etching rate continued to drop in the same manner for more than 30 minutes after this.

[0070] It was expected that as the pressure waiting time had passed, replacement and homogenization by the process gas in the decompression chamber 33 would progress further, and processing reproducibility would improve (the error bars would become shorter). However, an unexpected phenomenon that became clear for the first time through this experiment was that the etching rate significantly decreased as the pressure waiting time passed and the atmosphere in the decompression chamber 33 became stable.

[0071] The "pressure waiting time" and the processing time in the plasma processing apparatus 500 are not necessarily synonymous, but may be considered as related parameters. In this case, if the etching rate changes (decreases) when the pressure waiting time is long, this means that the etching rate may decrease "during processing of the workpiece."

[0072] For example, when processing a large workpiece, specifically, when attempting to flatten a silicon wafer or the like having a large diameter, several tens of minutes or more may be required from start to finish of processing. In this case, the decrease in the etching rate from the beginning to the end of processing means that, when viewed as a whole workpiece, there will be a difference in the degree of processing between the parts processed initially and those processed later (the reproducibility of processing over time will decrease).

[0073] In summary, if the process gas concentration and its uniformity in the decompression chamber 33 were the only parameters that affected the processing reproducibility, it was thought that purging or lengthening the pressure standby time would result in more stable and better processing stability. However, the experimental results revealed that in the conventional plasma processing apparatus 500, simply purging or lengthening the pressure standby time would improve the processing reproducibility (variation at a certain time) at a certain time, but would result in a decrease in the etching rate over time. Considering that the pressure standby time has the same significance as the processing time, a decrease in the etching rate over time suggests a decrease in the processing reproducibility over time.

[0074] Therefore, the inventors changed the conventional idea of ​​replacing the inside of the reduced pressure chamber 33 with a process gas and generating plasma in a stable atmosphere, and came up with the idea of ​​the plasma gun of the present invention (plasma gun 100) equipped with a gas supply unit that can constantly supply process gas to the suction end of the capillary tube. Conventionally, it has been believed that the "gas flow" caused by the process gas supplied from the gas supply unit can have a detrimental effect on the stability of plasma generation. In consideration of this, in the conventional plasma processing apparatus 500, the process gas is supplied from the side of the reduced pressure chamber 33 so that plasma is generated in a more uniform and stable process gas atmosphere and in an environment without a significant gas flow.

[0075] In the case of a normal plasma gun (jet type plasma gun), the above gas flow hardly poses a problem in the first place because the configuration is such that the process gas is sprayed. However, (1) in the case of a suction type plasma gun, the distance between the suction end and the workpiece is narrower than in the case of a jet type plasma gun, and (2) the suction type plasma gun is sensitive to the gas flow resulting from the pressure difference between the vacuum chamber and the plasma gun when suctioning the process gas, the exhaust speed, and the flux, etc., so that a method of constantly supplying the process gas to the suction end of the capillary tube has not been considered in a plasma processing device having a suction type plasma gun.

[0076] The inventors of the present invention, without being bound by the above-mentioned technical common sense, continued to steadily research the plasma gun of the present invention by repeatedly making prototypes and conducting simulations to verify its effects. Figure 5 shows one of the results, which is a graph showing the relationship between the "pressure waiting time" from the introduction of the process gas to the start of processing in a plasma processing device equipped with a plasma gun 100 and the etching rate. The error bars indicate the variation in the etching rate.

[0077] 5, in the plasma processing apparatus of the present invention, the etching rate was about 6.4 μm / min after 5 minutes of pressure standby time, and about 6.2 μm / min after 30 minutes of pressure standby time. At this time, the amount of decrease was 0.2 μm / min, which is about 3.1% in terms of the decrease rate. Compared with the results of FIG. 4, it can be said that both the decrease rate and the variation in the etching rate are extremely low.

[0078] From the above results, it became clear that in the plasma processing apparatus equipped with the plasma gun of the present invention, the variation is small whether the pressure standby time is short or not (having excellent processing reproducibility), and furthermore, even if the pressure standby time is long, the etching rate is less likely to decrease and is more stable than the conventional apparatus. The above was an unexpected result that overturned conventional expectations.

[0079] With the plasma gun of the present invention, excellent processing reproducibility can be obtained without replacing the gas in the reduced pressure chamber 33. Replacement of the process gas in the reduced pressure chamber 33 takes time, and the cost is likely to be excessively high due to the process gas used for the replacement. On the other hand, by using the plasma gun of the present invention, the same or better effect can be obtained without replacing the gas in the reduced pressure chamber 33 with the process gas.

[0080] Conventionally, purging of the decompression chamber 33 has been considered essential, and furthermore, gas supply during purging has been considered to have to be performed from the decompression chamber 33 side so as to avoid the generation of significant gas flow as much as possible. However, the inventors of the present invention have flexibly changed their ideas without being bound by common technical knowledge, and have completed a plasma gun 100 that provides effects completely different from those of conventional plasma guns.

[0081] It has been revealed that the plasma processing apparatus of the present invention does not require replacement with a process gas, and furthermore, the etching rate remains stable even over the course of processing time, resulting in excellent processing reproducibility over time. The above phenomenon occurring in conventional devices and the effects of the present invention were first clarified by the inventors in demonstration experiments, and the mechanisms are not necessarily clear. However, it became clear through experiments that the desired processing reproducibility cannot be obtained by gas replacement in the decompression chamber 33 and sufficient pressure waiting time alone, and that it is only possible to achieve this by the plasma gun (plasma gun 100) having the structure of the present invention.

[0082] [Example 2] Another embodiment of the plasma gun of the present invention will be described with reference to the drawings. Fig. 6 is a schematic diagram for explaining the structure of another embodiment of the plasma gun of the present invention. Fig. 6(a) is a cross-sectional view taken along CC, and Fig. 6(b) is a bottom view. The following mainly describes the differences between the plasma gun 100 and its modified plasma gun 110, and matters not described below are the same as those of the plasma gun 100.

[0083] The plasma gun 300 has a gas supply unit 13D configured with a double tube, similar to the plasma gun 110. Of these, the inner tube 43 has a flange portion 44 that protrudes radially toward the capillary tube 10 from the end having the supply hole 14A, and this is joined to the outer periphery of the capillary tube 10. The electrode 20 is disposed so as to surround the outer periphery of the capillary tube 10. Therefore, the electrode 20 is disposed in a space defined by the outer periphery of the capillary tube 10, the inner tube 43 of the gas supply unit 13D, and the flange portion 44 thereof.

[0084] In the plasma gun 300, the suction end 11, the supply hole 14A, and the electrode 20 are partitioned by the inner tube 43 of the gas supply unit 13D. That is, in the plasma gun 300, the inner tube 43 of the gas supply unit 13D functions as a partition unit. In other words, the gas supply unit 13D also functions as a partition unit.

[0085] Although the plasma gun 300 has the guide 16 so as to surround the outer periphery of the outer tube 42 of the gas supply unit 13D, this is not limited to the above, and the outer tube 42 and the guide 16 may be integrated together. That is, the gas supply unit 13D may also have the function of the guide 16. Furthermore, the plasma gun 300 does not have a shower plate, but may have one.

[0086] Since the plasma gun 300 has the gas supply unit 13D that also functions as a partition, the overall structure is simpler and has excellent maintainability.

[0087] [Example 3] Another embodiment of the plasma gun of the present invention will be described with reference to the drawings. Fig. 7 is a schematic diagram for explaining the structure of another embodiment of the plasma gun of the present invention. Fig. 7(a) is a schematic diagram of the tip of the capillary tube 10, and Fig. 7(b) is a bottom view of the corresponding part. The following mainly describes the differences from the plasma gun 100, and matters not described below are the same as those of the plasma gun 100.

[0088] The plasma gun 400 has a gas supply unit 13E, which is a tubular member wound around the outer periphery of the capillary tube 10 via a partition 15. A plurality of supply holes 14A are arranged in the body of the gas supply unit 13E. The process gas is supplied from the plurality of supply holes 14A to the suction end 11. The rest of the configuration is the same as that of the plasma gun 100.

[0089] The plasma gun 400 has multiple supply holes 14A, allowing for more efficient supply of process gas.

[0090] The plasma gun 400 has a gas supply unit 13E that is a tubular member, and the supply holes 14A can be freely arranged therein. Therefore, even if the supply holes 14A are to be added as necessary, it is only necessary to make new holes in the tubular member, which has the effect of making adjustments easier. In addition, since the supply holes 14A can be easily added, the effect of the present invention can be easily obtained without finely adjusting parameters such as the flow rate of the process gas.

[0091] [Example 4] Next, the relationship between the distance c between the capillary tube 10 and the gas supply parts 13A, B, and the distance b between the capillary tube 10 and the guide 16 in the plasma gun of the present invention will be described with reference to the drawings.

[0092] 9 is a schematic diagram of a plasma processing apparatus 600 equipped with a plasma gun of the present invention used in an experiment. The capillary tube 10, gas supply units 13A and 13B, and each unit connected to the electrode 20 are omitted from the illustration. The plasma processing apparatus 600 has the same configuration as the plasma processing apparatus 200, except that it does not have a shower plate 17. Here, only the parts necessary for explaining the experiment will be described.

[0093] [Table 1]

[0094] The above is a table showing the processing conditions. Under the above conditions, the etching rate (processing rate) and processing reproducibility (reproducibility) were investigated while changing b and c. FIG. 10 shows the results of investigating the reproducibility (processing reproducibility) and processing rate (etching rate) by changing the distance c between the axis of the capillary tube 10 and the axis of the gas supply part 13B (13A).

[0095] 10, it was found that the larger c is, that is, the greater the distance between the capillary tube 10 and the gas supply unit 13B (13A), the higher the processing rate is. On the other hand, it was found that the closer the distance between the capillary tube 10 and the gas supply unit 13B (13A), the higher the processing reproducibility is.

[0096] FIG. 11 shows the results of investigating the reproducibility (processing reproducibility) and processing rate (etching rate) by changing the distance b between the axis of the capillary tube 10 and the tip of the guide 16. 11, almost no change was observed in the processing rate even when the distance b between the capillary tube 10 and the tip of the guide 16 was changed. On the other hand, it was found that the processing repeatability was higher as the distance b between the capillary tube 10 and the tip of the guide 16 was shorter.

[0097] [Example 5] Next, the results of an experiment conducted to examine the effect of the guide 16 in the plasma gun of the present invention will be described. Fig. 12 is a schematic diagram of one embodiment (Example 5) of the plasma gun of the present invention used in the experiment. Fig. 12(a) is a DD cross-sectional view, and Fig. 12(b) is a bottom view thereof. In the following, differences from the plasma gun 100 will be mainly described, and those not described are the same as the plasma gun 100.

[0098] The plasma gun 710 has four gas supply parts (13A, 13B, 13C, 13D) arranged at 90° rotational symmetry with respect to the axis of the capillary tube 10. The guide 16 surrounding these parts is shaped like stacked rectangular columns with different hole diameters connected at connectors, and the hole diameter narrows in the direction toward the suction end 11.

[0099] 13 is a partial cross-sectional view of a plasma processing apparatus 700 having the above-mentioned plasma gun. Since the hole diameter of plasma gun 710 is narrowed in the direction toward suction end 11, distance c between capillary tube 10 and each of gas supply units 13A, 13B, 13C, and 13D is adjusted to be larger than distance b between capillary tube 10 and guide 16.

[0100] 12 and 13, capillary tube 10, gas supply units 13A, 13B, 13C, and 13D, and units connected to electrode 20 and the like are omitted from the illustration. Furthermore, plasma processing apparatus 700 does not include shower plate 17, but it is preferable that it does include shower plate 17.

[0101] Using this plasma processing apparatus 700, processing was performed under the same conditions (Table 1) as in Example 4. Table 2 shows the results.

[0102] [Table 2]

[0103] In Table 2, "Processing reproducibility" indicates the processing reproducibility when "purging" was not performed. Among the above results, the "Comparative Example" is the result of plasma processing apparatus 500 having a conventional plasma gun shown in Fig. 8, and when "purging" was not performed, the processing reproducibility was ±3.1%. On the other hand, "Example 5 (with guide)" is the result using plasma processing apparatus 700. In this case, the processing repeatability improved to ±0.4% without "purging."

[0104] Incidentally, "Example (without guide)" refers to the result when using a plasma processing apparatus similar to plasma processing apparatus 700, except that it does not have guide 16. In this case, the processing repeatability was ±1.2% without "purging."

[0105] From the above results, it was found that the plasma processing apparatus having the plasma gun of the present invention can obtain excellent processing reproducibility even without performing "purging." Furthermore, it was found that when the plasma gun has the guide 16, even better processing reproducibility can be obtained.

[0106] [Demonstration experiment 2] Using a plasma processing device equipped with a plasma gun 100, the degree of stabilization of the device when process gas was supplied for 20 seconds was evaluated by computer simulation, with the radius of the capillary tube (m), the distance D (m) from the center of the suction end to the supply hole, and the flow rate of the process gas supplied from the supply hole being V (m / s). The simulation parameters are as shown in the table below. The simulation was performed with the position of the gas supply hole at a distance of 5.0 x 10 -2 , 9.3×10 -2 , 1.4×10 -1 The gas supply holes were arranged symmetrically with respect to the axis of the capillary tube. [Table 3]

[0107] The degree of stabilization (stability) is defined as the degree at which processing can be started, which is 100%, and it is preferable that this degree reaches 100% within a shorter time. The results were evaluated according to the following criteria, and are shown in Table 3. In all cases, the stability when the process gas was supplied for 20 seconds was high, compared to the conventional plasma processing device.

[0108] (standard) A Stability was over 80%. B Stability was greater than 65% and less than 80%. C Stability was greater than 35% and less than 65%. D Stability was less than 35%.

[0109] [Table 4]

[0110] From the results in Table 4, D / V is 1.0×10 -3 That's it, 7.0 x 10 -1 Example 1, in which the temperature was less than 100° C., had better stability than Examples 10 to 12. In addition, D / V is 1.0×10 -3 That's it, 7.0 x 10 -2 Example 1, which is less than 100%, had better stability than Examples 4 and 5. [Explanation of symbols]

[0111] 10: capillary tube, 11: suction end, 12: exhaust end, 13A, 13B, 13C, 13D, 13E: gas supply unit, 14A, 14B: supply hole, 15: partition unit, 16: guide, 17: shower plate, 18: through hole, 20: electrode, 30: exhaust module, 31: process gas supply module, 32: high frequency power source, 33: decompression chamber, 34: workpiece, 35: workpiece support table, 36: moving mechanism, 40, 42: outer tube, 41, 43: inner tube, 44: flange unit, 50: gas supply unit, 100, 110, 300, 400, 710: plasma gun, 200, 500, 700: plasma processing device

Claims

1. a capillary tube having an intake end for drawing in a process gas and an exhaust end connected to an exhaust device; an electrode disposed so as to surround the outer periphery of the capillary tube and connected to a high frequency power source; a gas supply unit having a supply hole for supplying the process gas from the outside of the capillary tube toward the suction end; The electrode is provided with at least the suction end and a partition portion that defines the supply hole, A plasma gun in which, when the distance from the center of the suction end to the supply hole is D meters and the flow rate of the process gas supplied from the supply hole is V meters per second, D / V is 4.0×10 −1 or less.

2. a capillary tube having an intake end for drawing in a process gas and an exhaust end connected to an exhaust device; an electrode disposed so as to surround the outer periphery of the capillary tube and connected to a high frequency power source; a gas supply unit having a supply hole for supplying the process gas from the outside of the capillary tube toward the suction end; The electrode is provided with at least the suction end and a partition portion that defines the supply hole, The process gas supply system further includes a guide for suppressing diffusion of the process gas, The suction end is, compared with the supply hole and the tip of the guide, A plasma gun protruding axially from the exhaust end toward the suction end.

3. The plasma gun according to claim 2 , wherein the suction end, the supply hole, and the guide are arranged in a substantially concentric shape in this order from the center, with the suction end as the center.

4. The plasma gun of claim 3 , wherein the guide is disposed around an outer periphery of the capillary tube.

5. A capillary tube is provided between the guide and the capillary tube. a shower plate covering the supply hole to separate the suction end from the supply hole; 5. The plasma gun according to claim 2, wherein the shower plate has through holes for passing the process gas to the suction end side.

6. 5. The plasma gun according to claim 2, wherein the gas supply unit includes a tubular member wound around an outer periphery of the capillary tube, and a plurality of the supply holes are arranged in a body portion of the tubular member.

7. The electrodes are placed in an atmospheric pressure environment; 3. The plasma gun according to claim 1, wherein plasma processing of the workpiece is performed by plasma generated near the suction end while flowing counter to a gas flow of the process gas flowing from the suction end adjacent to the workpiece under reduced pressure toward the exhaust end.

8. A plasma gun according to claim 1 or 2; A vacuum chamber for accommodating a workpiece; A plasma processing apparatus, wherein the plasma gun and the reduced pressure chamber are air-tightly connected so that at least the suction end and the supply hole are disposed within the reduced pressure chamber.

9. The electrodes are placed in an atmospheric pressure environment; 9. The plasma processing apparatus according to claim 8, wherein plasma processing of the workpiece is performed by plasma generated near the suction end while flowing counter to a gas flow of the process gas flowing from the suction end adjacent to the workpiece under reduced pressure toward the exhaust end.

Images