Plasma processing equipment

Abstract

To provide a plasma processing apparatus capable of forming a swirling flow necessary for stable plasma generation. [Solution] The plasma processing apparatus (1) includes an inner electrode (100), an electrode holder (200), an outer electrode (400), and a fin member (300). The fin member (300) includes an enclosure (310) and a plurality of swirling fins (320). An inlet is defined between the base ends of a pair of adjacent swirling fins among the plurality of swirling fins, and an outlet is defined between the tip ends of the pair of swirling fins. The ratio of the swirling length from the inlet to the outlet to the diameter of the outer peripheral surface of the enclosure (310) is four or more.

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus. [Background technology]

[0002] It is known that a torch used for plasma processing of a surface of a workpiece such as a synthetic resin generates a swirling flow of processing gas within the torch. For example, International Publication No. 2024 / 009422 discloses a plasma head including an inner electrode, an outer electrode, and a rectifying member disposed inside the outer electrode. The rectifying member includes a plurality of rectifying plates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2024 / 009422 Summary of the Invention [Problem to be solved by the invention]

[0004] The plasma head described in WO 2024 / 009422 does not provide a sufficient swirling effect, which can lead to unstable plasma generation.

[0005] An object of the present disclosure is to provide a plasma processing apparatus capable of forming a swirling flow necessary for stable plasma generation. [Means for solving the problem]

[0006] The plasma processing apparatus of the present disclosure comprises an inner electrode to which a voltage is applied, an electrode holder that holds the inner electrode, an outer electrode that surrounds the inner electrode and the electrode holder, and a fin member that is provided between the electrode holder and the outer electrode and that forms a swirling flow around the inner electrode by swirling a processing gas supplied inside the outer electrode, wherein the fin member includes an enclosing portion that surrounds the tip end of the electrode holder and a plurality of swirling fins provided on the outer peripheral surface of the enclosing portion, wherein an inlet is defined between each base end of a pair of adjacent swirling fins among the plurality of swirling fins, and an outlet is defined between each tip end of the pair of swirling fins, and the ratio of the length from the inlet to the outlet to the diameter of the outer peripheral surface of the enclosing portion is four or more.

[0007] The plasma processing apparatus of the present disclosure comprises an inner electrode to which a voltage is applied, an electrode holder that holds the inner electrode, an outer electrode that surrounds the inner electrode and the electrode holder, and a fin member that is provided between the electrode holder and the outer electrode and that forms a swirling flow around the inner electrode by swirling a processing gas supplied inside the outer electrode, wherein the fin member includes an enclosing portion that surrounds the tip end of the electrode holder and a plurality of swirling fins provided on the outer surface of the enclosing portion, wherein an inlet is defined between each base end of a pair of adjacent swirling fins among the plurality of swirling fins, and an outlet is defined between each tip end of the pair of swirling fins, and the ratio of the swirling length from the inlet to the outlet to the axial length of the portion of the enclosing portion where the plurality of swirling fins are formed is two or more. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a plasma processing apparatus capable of forming a swirling flow necessary for stable plasma generation. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a perspective view of a plasma processing apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of the plasma processing apparatus shown in FIG. [Figure 3] FIG. 3 is a perspective view showing a cross section taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a perspective view showing a cross section taken along line IV-IV in FIG. 2. [Figure 5] FIG. [Figure 6] FIG. 6 is a perspective view showing a cross section taken along line VI-VI in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0011] Fig. 1 is a perspective view of a plasma processing apparatus according to an embodiment of the present disclosure. Fig. 2 is a plan view of the plasma processing apparatus shown in Fig. 1. Fig. 3 is a perspective view showing a cross section taken along line III-III in Fig. 2. Fig. 4 is a perspective view showing a cross section taken along line IV-IV in Fig. 2. This plasma processing apparatus 1 is suitably used for surface modification of a workpiece, etc.

[0012] As shown in Figures 1 to 4, the plasma processing apparatus 1 includes an inner electrode 100, an electrode holder 200, a fin member 300, a flow path defining member 350, a bearing receiving portion 360, an outer electrode 400, a support plate 500, a storage portion 550, and a drive mechanism 600.

[0013] The inner electrode 100 has a shape that extends linearly. The inner electrode 100 is made of, for example, tungsten. A voltage is applied to the inner electrode 100 from a power supply (not shown).

[0014] The electrode holder 200 holds the inner electrode 100. The electrode holder 200 is made of a conductor. The electrode holder 200 has an inner holder 210, an outer holder 220, and a block portion 230.

[0015] The inner holding body 210 holds the inner electrode 100 while contacting the outer peripheral surface of the inner electrode 100. The inner holding body 210 has a shape that extends in a direction parallel to the central axis AX of the inner electrode 100 (see FIGS. 3 and 4). The inner holding body 210 holds the rear part of the inner electrode 100. The inner holding body 210 is made of, for example, copper. A slit that extends in a direction parallel to the axial direction of the inner holding body 210 is formed at the tip part of the inner holding body 210.

[0016] The outer holder 220 surrounds the inner holder 210. The outer holder 220 surrounds the inner holder 210 so as to expose the base end of the inner holder 210. A reduced diameter section 222 is formed at the tip end of the outer holder 220. The reduced diameter section 222 has an inner circumferential surface whose diameter gradually decreases toward the tip end. Therefore, when the inner holder 210 is inserted into the outer holder 220, the tip end of the inner holder 210 is pressed by the reduced diameter section 222 of the outer holder 220 and is brought into pressure contact with the inner electrode 100.

[0017] The block portion 230 is connected to the base end of the outer holding body 220. The block portion 230 is formed in a circular ring shape that surrounds the outer holding body 220. A voltage is applied to the block portion 230.

[0018] The fin member 300 is provided around the outer holder 220. The fin member 300 swirls the processing gas (argon, air, etc.) to form a swirling flow SW (see FIG. 3) around the inner electrode 100. The fin member 300 is made of an insulating material such as ceramics.

[0019] Fig. 5 is a perspective view of the fin member. Fig. 6 is a perspective view showing a cross section taken along line VI-VI in Fig. 5. As shown in Figs. 5 and 6, the fin member 300 has an enclosing portion 310 and a plurality of swivel fins 320.

[0020] The surrounding portion 310 surrounds at least the tip portion of the electrode holder 200. The surrounding portion 310 surrounds the tip portion of the inner holder 210 and the tip portion of the outer holder 220. The surrounding portion 310 has a cylindrical outer peripheral surface.

[0021] The plurality of swirl fins 320 are provided on the outer peripheral surface of the enclosure 310. The plurality of swirl fins 320 have a shape that causes the processing gas supplied along the axial direction of the enclosure 310 to swirl in the circumferential direction of the enclosure 310.

[0022] A plurality of inlets 301 to 304 are provided at the base ends of the plurality of swirl fins 320. A plurality of outlets 305 to 308 are provided at the tip ends of the plurality of swirl fins 320. In this embodiment, the plurality of inlets 301 to 304 includes four inlets, and the plurality of outlets 305 to 308 includes four outlets. That is, in this embodiment, the plurality of swirl fins 320 includes four swirl fins 320. However, the number of swirl fins 320 is not limited to four. Note that the processing gas flowing in from the inlet 301 flows out from the outlet 305, the processing gas flowing in from the inlet 302 flows out from the outlet 306, the processing gas flowing in from the inlet 303 flows out from the outlet 307, and the processing gas flowing in from the inlet 304 flows out from the outlet 308.

[0023] Each of the swirl fins 320 may be shaped to swirl the process gas around the enclosure 310 1.5 times or more as the process gas travels from the inlet to the outlet.

[0024] The ratio of the swirling length SL (see Figure 5) from each inlet to each outlet to the axial length L (see Figure 5) of the portion of the surrounding portion 310 where the multiple swirling fins 320 are formed is preferably 2 to 30 times, and more preferably 5 to 15 times.

[0025] The ratio of the swirling length SL from each inlet to each outlet to the diameter R of the outer peripheral surface of the surrounding portion 310 (see Figure 6) is preferably 4 to 40 times, more preferably 10 to 30 times, and even more preferably 13 to 20 times.

[0026] 5, the "swirl length SL from each inlet to each outlet" refers to the length traveling between the pair of swirling fins 320 while swirling around the enclosure 310 from a portion located between the base ends of a pair of adjacent swirling fins 320 on the outer circumferential surface of the enclosure 310 to a portion located between the tip ends of the pair of swirling fins 320. Note that FIG. 5 illustrates an example of the swirling length SL from the inlet 301 to the outlet 305.

[0027] 3 and 4, the flow path regulating member 350 is provided around the fin member 300. The flow path regulating member 350 has an inner circumferential surface 350s that faces the outer end surfaces of each of the swirl fins 320. The gap between this inner circumferential surface 350s and the outer circumferential surface of each of the swirl fins 320 is set to an extent that the process gas does not substantially pass through. The inner circumferential surface 350s may be in contact with the outer circumferential surface of each of the swirl fins 320.

[0028] 3, the flow path defining member 350 includes a support portion 352 that supports the tip end of the fin member 300. The support portion 352 is formed at the tip end of the flow path defining member 350. The support portion 352 has a shape that protrudes from the inner circumferential surface 350s toward the inner electrode 100. The support portion 352 has gas insertion holes 352h that allow the swirling flow formed by each swirling fin 320 to pass through.

[0029] The bearing receiving portion 360 receives the bearing Be. The bearing Be is disposed around the fin member 300 and surrounds the fin member 300. The bearing receiving portion 360 is connected to the base end of the flow path defining member 350. The bearing receiving portion 360 has an inner circumferential surface 360s that faces the outer circumferential surface of each swirl fin 320. The gap between this inner circumferential surface 360s and the outer circumferential surface of each swirl fin 320 is set to an extent that the process gas does not substantially pass through. The inner circumferential surface 360s may be in contact with the outer circumferential surface of each swirl fin 320. The intermediate member 250 is connected to the base end of the bearing receiving portion 360.

[0030] The outer electrode 400 surrounds a portion of the inner electrode 100 and the electrode holder 200. The outer electrode 400 is rotatable around the central axis AX of the inner electrode 100 relative to the inner electrode 100, the electrode holder 200, and the fin member 300. The outer electrode 400 has a rotatable nozzle 410 and a power feed tip 420.

[0031] The rotary nozzle 410 is connected to ground. The rotary nozzle 410 is rotationally driven by a drive mechanism 600. The rotary nozzle 410 surrounds the flow path defining member 350. In other words, the fin member 300 and the flow path defining member 350 are provided between the electrode holder 200 and the outer electrode 400.

[0032] The power feed tip 420 is fixed to the tip of the rotary nozzle 410 so as to be detachable from the tip. The power feed tip 420 is provided with a blowout hole 420h. The center of the blowout hole 420h at its base end (the end closer to the inner electrode 100) is located approximately on an extension of the central axis AX. The center of the blowout hole 420h at its tip end (the end from which plasma is blown out) is spaced apart from the extension of the central axis AX in a direction perpendicular to the central axis AX. However, the center of the blowout hole 420h at its tip end may also be located approximately on an extension of the central axis AX.

[0033] The support plate 500 supports the inner electrode 100, the electrode holder 200, and the fin members 300. In this embodiment, the support plate 500 supports the inner electrode 100, the electrode holder 200, and the fin members 300 via an intermediate member 250. As shown in FIGS. 3 and 4 , the intermediate member 250 supports the base end portion 312 of the surrounding portion 310.

[0034] 4, a supply flow path FL is formed in the intermediate member 250 to supply a process gas around the fin member 300. A supply pipe 10 is connected to the upstream end of the supply flow path FL. The downstream end of the supply flow path FL faces a portion of the outer circumferential surface of the enclosure member 310 between the base end 312 and each of the swirl fins 320.

[0035] The process gas supplied to the supply flow path FL through the supply pipe 10 flows downstream while contacting the outer circumferential surface of the enclosure 310, passing between the fin member 300 and the bearing receiving portion 360, and between the fin member 300 and the flow path defining member 350. At this time, a swirling flow SW is formed by the action of each swirling fin 320. The direction of this swirling flow SW is the same as the rotation direction of the rotary nozzle 410.

[0036] The driving mechanism 600 rotates the outer electrode 400. The driving mechanism 600 has a motor M, a first gear 610, a second gear 620, and a bearing holder 630.

[0037] The motor M is fixed to the support plate 500. The output shaft of the motor M passes through the support plate 500.

[0038] The first gear 610 is connected to the output shaft of the motor M.

[0039] The second gear 620 is disposed so as to mesh with the first gear 610. The second gear 620 surrounds the fin member 300. The center of rotation of the second gear 620 is located on the central axis AX.

[0040] The bearing holder 630 is fixed to the second gear 620. Specifically, the bearing holder 630 is fixed to the second gear 620 by a fastening member so as to rotate integrally with the second gear 620. A bearing Be is disposed inside the bearing holder 630. That is, the bearing Be is disposed between the bearing holder 630 and the bearing receiver 360.

[0041] However, for example, a belt, a pulley, a roller chain, or a sprocket may be used instead of the first gear 610, the second gear 620, and the bearing holder 630. Also, instead of the motor M, a power source that generates a rotational force, such as a gasoline engine, a diesel engine, or a rotary cylinder, may be used.

[0042] The base end of the rotary nozzle 410 is connected to the bearing holder 630 by a fastening member. This causes the rotary nozzle 410 to rotate together with the bearing holder 630 and the second gear 620. The rotation direction AR of the rotary nozzle 410 (see FIG. 3) is the same as the direction of the swirling flow SW formed after passing through the fin member 300.

[0043] The accommodation portion 550 accommodates the first gear 610, the second gear 620, and the bearing holder 630. The accommodation portion 550 is connected to the support plate 500. The accommodation portion 550 has an accommodation wall 552 and a lid 554.

[0044] The containing wall 552 is connected to the support plate 500. The containing wall 552 surrounds the first gear 610, the second gear 620, and the bearing holder 630.

[0045] The lid 554 is fixed to the containing wall 552 so as to close the opening of the containing wall 552. The lid 554 is formed with an insertion hole 554h through which the base end of the rotary nozzle 410 is inserted.

[0046] In the plasma processing apparatus 1 described above, when a processing gas is supplied to the supply flow path FL through the supply pipe 10, the processing gas flows downstream while contacting the outer peripheral surface of the enclosure 310, and passes between the fin member 300 and the bearing support member 360, and between the fin member 300 and the flow path defining member 350. At this time, the processing gas advances while swirling between the swirling fins 320, and flows out through the gas insertion holes 352h of the support portion 352. As a result, a swirling flow SW is formed downstream of the fin member 300, and this swirling flow SW is converted into plasma between the inner electrode 100 and the rotary nozzle 410.

[0047] On the other hand, when the motor M of the drive mechanism 600 is driven, the rotary nozzle 410 rotates around the central axis AX via the first gear 610, the second gear 620, and the bearing holder 630. The rotation direction AR of this rotary nozzle 410 is the same as the direction of the swirling flow SW. This promotes the rotation of the swirling flow SW, making the generation of plasma more stable.

[0048] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0049] [Aspect 1] an inner electrode to which a voltage is applied; an electrode holder that holds the inner electrode; an outer electrode surrounding the inner electrode and the electrode holder; a fin member provided between the electrode holder and the outer electrode, the fin member swirling a processing gas supplied to the inside of the outer electrode to form a swirling flow around the inner electrode, The fin member is a surrounding portion surrounding the tip portion of the electrode holder; a plurality of swirl fins provided on the outer peripheral surface of the surrounding portion, an inlet is defined between base ends of a pair of adjacent swirl fins among the plurality of swirl fins, and an outlet is defined between tip ends of the pair of swirl fins, A plasma processing apparatus, wherein a ratio of a swirling length from the inlet to the outlet to a diameter of the outer circumferential surface of the surrounding portion is 4 or more.

[0050] In this plasma processing apparatus, the ratio of the swirling length from the inlet to the outlet to the diameter of the outer peripheral surface of the enclosure is four or more, so that a swirling flow necessary for stable plasma generation is formed.

[0051] [Aspect 2] 2. The plasma processing apparatus according to claim 1, wherein a ratio of the swirling length from the inlet to the outlet to the axial length of the portion of the surrounding portion where the plurality of swirling fins are formed is two or more.

[0052] [Aspect 3] a flow path defining member disposed between the fin member and the outer electrode; 3. The plasma processing apparatus according to aspect 1 or 2, wherein the flow path defining member has an inner circumferential surface facing an outer end surface of each of the swirl fins.

[0053] In this embodiment, a flow path for the process gas is defined between the flow path defining member and each swirling fin, so that a swirling flow is effectively formed.

[0054] [Aspect 4] 4. The plasma processing apparatus according to aspect 3, wherein the flow path defining member includes a support portion that has a shape that protrudes from the inner circumferential surface toward the inner electrode and supports a tip end of the fin member.

[0055] In this embodiment, misalignment between the central axes of the fin member and the inner electrode and the outer electrode is suppressed.

[0056] [Aspect 5] 5. The plasma processing apparatus of claim 4, wherein the support portion has gas insertion holes through which the swirling flow formed by the plurality of swirling fins passes.

[0057] [Aspect 6] the outer electrode is rotatable relative to the inner electrode, the electrode holder, and the fin member about a central axis of the inner electrode, 6. The plasma processing apparatus according to any one of aspects 1 to 5, wherein the rotation direction of the outer electrode is the same as the rotation direction of the swirling flow.

[0058] In this embodiment, the rotation of the swirling flow is promoted by the outer electrode, so that the generation of plasma becomes more stable.

[0059] [Aspect 7] an inner electrode to which a voltage is applied; an electrode holder that holds the inner electrode; an outer electrode surrounding the inner electrode and the electrode holder; a fin member provided between the electrode holder and the outer electrode, the fin member swirling a processing gas supplied to the inside of the outer electrode to form a swirling flow around the inner electrode, The fin member is a surrounding portion surrounding the tip portion of the electrode holder; a plurality of swirl fins provided on the outer peripheral surface of the surrounding portion, an inlet is defined between base ends of a pair of adjacent swirl fins among the plurality of swirl fins, and an outlet is defined between tip ends of the pair of swirl fins, A plasma processing apparatus, wherein a ratio of a swirling length from the inlet to the outlet to an axial length of a portion of the surrounding portion where the plurality of swirling fins are formed is two or more.

[0060] In this plasma processing apparatus, the same effects as those of the first embodiment can be obtained.

[0061] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0062] 1 plasma processing apparatus, 100 inner electrode, 200 electrode holder, 210 inner holder, 220 outer holder, 230 block portion, 300 fin member, 310 surrounding portion, 320 swirling fin, 350 flow path defining member, 350s inner peripheral surface, 352 support portion, 352h gas insertion hole, 360 bearing receiving portion, 360s inner peripheral surface, 400 outer electrode, 410 rotating nozzle, 420 power supply tip, 500 support plate, 550 storage portion, 552 storage wall, 554 lid, 554h insertion hole, 600 drive mechanism, 610 first gear, 620 second gear, 630 bearing holder, Be bearing, FL supply flow path, M motor, SL swirl length, SW swirl flow.

Claims

1. an inner electrode to which a voltage is applied; an electrode holder that holds the inner electrode; an outer electrode surrounding the inner electrode and the electrode holder; a fin member provided between the electrode holder and the outer electrode, the fin member swirling a processing gas supplied to the inside of the outer electrode to form a swirling flow around the inner electrode, The fin member is a surrounding portion surrounding the tip portion of the electrode holder; a plurality of swirl fins provided on the outer peripheral surface of the surrounding portion, an inlet is defined between base ends of a pair of adjacent swirl fins among the plurality of swirl fins, and an outlet is defined between tip ends of the pair of swirl fins, A plasma processing apparatus, wherein a ratio of a swirling length from the inlet to the outlet to a diameter of the outer circumferential surface of the surrounding portion is four or more.

2. 2. The plasma processing apparatus according to claim 1, wherein a ratio of the swirling length from the inlet to the outlet to an axial length of a portion of the surrounding portion where the plurality of swirling fins are formed is two or more.

3. a flow path defining member disposed between the fin member and the outer electrode; The plasma processing apparatus according to claim 1 , wherein the flow path defining member has an inner circumferential surface facing an outer end surface of each of the swirl fins.

4. The plasma processing apparatus according to claim 3 , wherein the flow path defining member includes a support portion that has a shape that protrudes from the inner circumferential surface toward the inner electrode and that supports a tip end of the fin member.

5. The plasma processing apparatus according to claim 4 , wherein the support portion has gas passage holes through which the swirling flow formed by the plurality of swirling fins passes.

6. the outer electrode is rotatable relative to the inner electrode, the electrode holder, and the fin member about a central axis of the inner electrode, The plasma processing apparatus according to claim 1 , wherein the rotation direction of the outer electrode is the same as the rotation direction of the swirling flow.

7. an inner electrode to which a voltage is applied; an electrode holder that holds the inner electrode; an outer electrode surrounding the inner electrode and the electrode holder; a fin member provided between the electrode holder and the outer electrode, the fin member swirling a processing gas supplied to the inside of the outer electrode to form a swirling flow around the inner electrode, The fin member is a surrounding portion surrounding the tip portion of the electrode holder; a plurality of swirl fins provided on the outer peripheral surface of the surrounding portion, an inlet is defined between base ends of a pair of adjacent swirl fins among the plurality of swirl fins, and an outlet is defined between tip ends of the pair of swirl fins, A plasma processing apparatus, wherein a ratio of a swirling length from the inlet to the outlet to an axial length of a portion of the surrounding portion where the plurality of swirling fins are formed is two or more.

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