Plasma supply device
The plasma supply device addresses electrode wear in plasma supply devices by using insulating portions and a protective layer to maintain efficiency and reduce costs, thereby extending electrode lifespan.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- THREE TEC CO LTD
- Filing Date
- 2024-11-05
- Publication Date
- 2026-05-19
AI Technical Summary
Conventional plasma supply devices face electrode consumption issues due to plasma exposure, leading to increased manufacturing costs when protective measures like ceramic coating are employed.
The plasma supply device incorporates a cylindrical first electrode with insulating portions and an outer casing, maintaining a specific aspect ratio and optionally a protective layer, to reduce electrode wear while controlling manufacturing costs.
This design effectively reduces electrode wear and consumption, maintaining plasma generation efficiency at a lower cost compared to conventional methods.
Smart Images
Figure 2026081512000001_ABST
Abstract
Description
Technical Field
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[0001] The present invention relates to a plasma supply device that supplies plasma toward a space that requires plasma.
Background Art
[0002] Conventionally, a plasma supply device including a first electrode having a cylindrical shape, a second electrode located at one end of the first electrode, and a gas introduction path for introducing a gas to be plasmaized has been known (for example, see Patent Documents 1 and 2). This type of plasma supply device generates plasma by plasmaizing the introduced gas inside the first electrode, and supplies this plasma from the other end of the first electrode toward a space that requires plasma.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the above conventional plasma supply device, the other end of the first electrode, which is the plasma outlet, may be damaged and consumed by the plasma. The consumption of this first electrode can be reduced by coating the inner peripheral surface of the first electrode with ceramic or the like. However, such a measure causes an increase in manufacturing cost.
[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a plasma supply device capable of reducing electrode consumption at low cost.
Means for Solving the Problems
[0006] To solve the above problems, the plasma supply device according to the present invention comprises a first electrode including a cylindrical portion and a cylindrical plug portion inserted from one end of the cylindrical portion, a first insulating portion surrounding the outer circumferential surface of the other end of the cylindrical portion, a second insulating portion surrounding the outer circumferential surface of the portion of the cylindrical portion other than the other end, and an outer casing serving as a second electrode surrounding the first insulating portion and the second insulating portion, wherein the cylindrical portion is longer than the cylindrical plug portion, and when the inner diameter of the portion of the space within the cylindrical portion not occupied by the cylindrical plug portion is Φ and its length is L, the value calculated by the formula "L / Φ" is 4 or less.
[0007] The first insulating portion of the plasma supply device described above may include an end-face covering portion that covers the end face of the other end of the cylindrical portion. In this case, it is preferable that the first insulating portion further includes an extension portion that extends from the end-face covering portion toward the axis of the cylindrical portion.
[0008] Preferably, the plasma supply device further includes a cylindrical protective layer that covers the inner circumferential surface of the cylindrical portion.
[0009] The first insulating layer and the cylindrical protective layer are made of, for example, ceramic. [Effects of the Invention]
[0010] According to the present invention, it is possible to provide a plasma supply device that can reduce electrode wear at a low cost. [Brief explanation of the drawing]
[0011] [Figure 1] This is a schematic end view showing a plasma supply device according to the first embodiment of the present invention. [Figure 2] This is a schematic end view showing a plasma supply device according to a second embodiment of the present invention. [Figure 3] This is a schematic end view showing a plasma supply device according to a third embodiment of the present invention. [Figure 4] This graph shows the measurement results of the plasma supply device according to the present invention. [Figure 5]This graph shows another measurement result for the plasma supply device according to the present invention. [Modes for carrying out the invention]
[0012] Hereinafter, embodiments of the plasma supply apparatus according to the present invention will be described with reference to the attached drawings.
[0013] [First Embodiment] Figure 1 shows a plasma supply device 10A according to the first embodiment of the present invention. The plasma supply device 10A is for supplying plasma to an external space that requires plasma (in this embodiment, the internal space of a process chamber), and as shown in the figure, it comprises a cylindrical plug portion 11 and a cylindrical portion 12 that constitute the first electrode (cathode), a first insulating portion 13A, a second insulating portion 14, and an outer casing portion 15 that constitutes the second electrode (anode).
[0014] The cylindrical portion 12 is a cylindrical member having two open ends. In this embodiment, the cylindrical portion 12 is made of aluminum.
[0015] The cylindrical plug portion 11 is a substantially cylindrical member having an insertion hole for inserting the terminal portion 16, and is inserted into the cylindrical portion 12 from one end of the cylindrical portion 12. The outer diameter of the cylindrical plug portion 11 is approximately equal to the inner diameter of the cylindrical portion 12. In this embodiment, the cylindrical plug portion 11 is made of aluminum.
[0016] The first insulating portion 13A includes a portion that surrounds the outer circumferential surface 12b of the other end of the cylindrical portion 12, that is, the end in which the cylindrical plug portion 11 is not inserted, and a portion that covers the end face 12a of the other end of the cylindrical portion 12 (end face covering portion). The end face covering portion of the first insulating portion 13A forms a plasma outlet with a diameter of Φ2. In this embodiment, the first insulating portion 13A is made of ceramic.
[0017] The second insulating portion 14 includes a portion surrounding the outer peripheral surface of a portion other than the other end portion of the cylindrical portion 12. The second insulating portion 13 is made of PEEK resin in the present embodiment.
[0018] The exterior portion 15 mainly includes a portion surrounding the second insulating portion 14, a portion (constricted portion) 15a surrounding the first insulating portion 13A at a position closer to the plasma outlet than this portion, and a portion (flange portion) 15b surrounding the first insulating portion 13A at a position even closer to the plasma outlet than the constricted portion 15a. The exterior portion 15 is made of aluminum in the present embodiment.
[0019] The plasma supply device 10A further includes the aforementioned terminal portion 16. The terminal portion 16 is electrically connected to the central conductor of the coaxial cable extending from the high-frequency power source RF and the cylindrical plug portion 11. When the terminal portion 16 is connected to the central conductor, the exterior portion 15 is electrically connected to the outer conductor (GND) of the coaxial cable.
[0020] The plasma supply device 10A generates plasma in a portion of the space inside the cylindrical portion 12 that is not occupied by the cylindrical plug portion 11, and supplies this plasma to the process chamber from the plasma outlet through the other end portion of the cylindrical portion 12. Hereinafter, this portion is referred to as the "plasma generation space". As shown in FIG. 1, the plasma generation space has a diameter of Φ1 and a length of L. In the present embodiment, the diameter Φ1 is equal to the diameter Φ2.
[0021] The plasma supply device 10A further includes a gas inlet 17 into which a gas to be plasmaized (in the present embodiment, NF3 gas) is injected, and gas flow paths 18, 19. The gas inlet 17 and the gas flow paths 18, 19 communicate with each other. Also, the gas flow path 19 communicates with the plasma generation space through a slight gap between the outer peripheral surface of the cylindrical plug portion 11 and the inner peripheral surface of the cylindrical portion 12.
[0022] The plasma supply device 10A is further equipped with a cooling medium channel 20. By passing a cooling medium (water in this embodiment) through the cooling medium channel 20, the cylindrical section 12 can be cooled. Note that in Figure 1, the path for supplying the cooling medium to the cooling medium channel 20 and the path for discharging the cooling medium from the cooling medium channel 20 are omitted. The same applies to Figures 2 and 3.
[0023] The plasma supply device 10A can also be used by attaching it to the outer wall W of the process chamber at the flange portion 15b of the outer casing 15.
[0024] [Second Embodiment] Figure 2 shows a plasma supply device 10B according to a second embodiment of the present invention. The plasma supply device 10B differs from the plasma supply device 10A in that it further comprises a cylindrical protective layer 21, but is otherwise identical to the plasma supply device 10A.
[0025] The cylindrical protective layer 21 covers at least the inner circumferential surface of the cylindrical portion 12 surrounding the plasma generation space. In this embodiment, the cylindrical protective layer 21 is made of ceramic.
[0026] [Third Embodiment] Figure 3 shows a plasma supply device 10C according to a third embodiment of the present invention. The plasma supply device 10C differs from the plasma supply device 10B in that it has a first insulating part 13C instead of a first insulating part 13A, but is otherwise identical to the plasma supply device 10B.
[0027] The first insulating portion 13C includes a portion surrounding the outer circumferential surface 12b of the other end of the cylindrical portion 12, an end-face covering portion covering the end face 12a of the other end of the cylindrical portion 12, and an extension portion extending from the end-face covering portion toward the axis of the cylindrical portion 12. In this embodiment, the extension portion, rather than the end-face covering portion, forms a plasma outlet with a diameter of Φ2. That is, in the first and second embodiments, Φ1 = Φ2, but in this embodiment, Φ1 > Φ2. In this embodiment, the first insulating portion 13C is made of ceramic.
[0028] Next, plasma supply devices according to the 1st to 7th embodiments and a plasma supply device according to the comparative example were fabricated, and the results of measuring the amount of consumption of the cylindrical portion 12 at the other end after supplying plasma for 1 hour and the decomposition rate after supplying plasma for 2 hours for each device will be described. In all measurements, the flow rate of NF3 gas injected into the gas inlet 17 was set to 60 sccm.
[0029] [First Embodiment] The plasma supply device according to this embodiment is the plasma supply device 10A according to the first embodiment, in which the length L of the plasma generation space is 36 mm and the diameter Φ1 is 12 mm. The diameter Φ2 of the plasma outlet is also 12 mm.
[0030] [Second Example] The plasma supply device according to this embodiment is the plasma supply device 10A according to the first embodiment, in which the length L of the plasma generation space is 36 mm and the diameter Φ1 is 10 mm. The diameter Φ2 of the plasma outlet is also 10 mm.
[0031] [Third Embodiment] The plasma supply device according to this embodiment is the plasma supply device 10A according to the first embodiment, in which the length L of the plasma generation space is 33 mm and the diameter Φ1 is 12 mm. The diameter Φ2 of the plasma outlet is also 12 mm.
[0032] [Fourth embodiment] The plasma supply device according to this embodiment is the plasma supply device 10A according to the first embodiment, in which the length L of the plasma generation space is 20 mm and the diameter Φ1 is 12 mm. The diameter Φ2 of the plasma outlet is also 12 mm.
[0033] [Fifth Example] The plasma supply device according to this embodiment is the plasma supply device 10B according to the second embodiment, in which the length L of the plasma generation space is 36 mm and the diameter Φ1 is 12 mm. The diameter Φ2 of the plasma outlet is also 12 mm.
[0034] [Sixth Example] The plasma supply device according to this embodiment is a plasma supply device 10C according to the third embodiment, in which the length L of the plasma generation space is 36 mm, the diameter Φ1 is 12 mm, and the diameter Φ2 of the plasma outlet is 10 mm.
[0035] [Sixth Example] The plasma supply device according to this embodiment is a plasma supply device 10C according to the third embodiment, in which the length L of the plasma generation space is 36 mm, the diameter Φ1 is 12 mm, and the diameter Φ2 of the plasma outlet is 6 mm.
[0036] [Comparative Example] The comparative example plasma supply device is the plasma supply device 10A according to the first embodiment, in which the length L of the plasma generation space is 36 mm and the diameter Φ1 is 6 mm. The diameter Φ2 of the plasma outlet is also 6 mm.
[0037] Table 1 and Figure 4 show the measurement results for the plasma supply devices related to the first to fourth examples and comparative examples. [Table 1]
[0038] These results indicate that the plasma supply devices according to the second embodiment, the first embodiment with an aspect ratio of 3.6 for the plasma generation space calculated by the formula “L / Φ1”, the third embodiment with an aspect ratio of 2.75, and the fourth embodiment with an aspect ratio of 1.67, consume significantly less and have a significantly higher decomposition rate compared to the comparative example plasma supply device with an aspect ratio of 6. In other words, these results indicate that sufficiently good consumption and decomposition rates can be obtained by setting the aspect ratio to approximately 4 or less.
[0039] Note that an error of approximately ±5% occurs in the measurement of the decomposition rate. Therefore, it is considered that there is no significant difference in the decomposition rate of the plasma supply devices according to the first to fourth embodiments.
[0040] Table 2 shows the measurement results for the plasma supply device according to the first and fifth embodiments. [Table 2]
[0041] These results indicate that the plasma supply device according to the fifth embodiment, which has a cylindrical protective layer 21 on the inner circumferential surface of the cylindrical portion 12, consumes less than the plasma supply device according to the first embodiment, which does not have the cylindrical protective layer 21. However, there is no significant difference in the decomposition rate.
[0042] Table 3 and Figure 5 show the measurement results for the plasma supply devices according to the 5th to 7th embodiments. [Table 3]
[0043] These results indicate that the plasma supply devices according to the 6th embodiment, with a plasma outlet diameter Φ2 of 10 mm, and the 7th embodiment, with a plasma outlet diameter Φ2 of 6 mm, consume less power compared to the plasma supply device according to the 5th embodiment, with a plasma outlet diameter Φ2 of 12 mm. In other words, these results indicate that restricting the plasma outlet with the first insulating section 13C reduces the amount of power consumed. However, there appears to be no significant difference in the decomposition rate.
[0044] Although the plasma supply apparatus according to the first to third embodiments of the present invention has been described above, the configuration of the present invention is not limited to these.
[0045] For example, the first insulating portion 13A does not necessarily include an end-face covering portion that covers the end face 12a of the other end of the cylindrical portion 12.
[0046] Furthermore, the cylindrical protective layer 21 may have a protrusion extending toward the axis of the cylindrical portion 12. In other words, the plasma generation space may be partially reduced in diameter. With this configuration, it is thought that an effect similar to that obtained when the plasma outlet is narrowed by the first insulating portion 13C can be obtained. [Explanation of Symbols]
[0047] 10A, 10B, 10C Plasma Supply Unit 11. Cylindrical section (first electrode) 12. Cylindrical plug section (first electrode) 13A, 13C First insulation section 14. Second insulating section 15 Exterior part (2nd electrode) 16 Terminal section 17 Gas inlet 18 Gas flow path 19 Gas flow path 20 Cooling medium flow path 21. Cylindrical protective layer
Claims
1. A first electrode including a cylindrical portion and a cylindrical plug portion inserted from one end of the cylindrical portion, A first insulating portion surrounds the outer circumferential surface of the other end of the cylindrical portion, A second insulating portion surrounds the outer circumferential surface of the portion of the cylindrical part other than the other end, The outer casing, which serves as the second electrode, surrounds the first insulating portion and the second insulating portion. Equipped with, The cylindrical portion is longer than the cylindrical plug portion. When the inner diameter of the space within the cylindrical portion that is not occupied by the cylindrical plug portion is Φ and the length is L, the value calculated by the formula "L / Φ" is 4 or less. A plasma supply device characterized by the following features.
2. The first insulating portion includes an end-face covering portion that covers the end face of the other end of the cylindrical portion. The plasma supply device according to feature 1.
3. The first insulating portion further includes an extension that extends from the end face covering portion toward the axis of the cylindrical portion. The plasma supply device according to feature 2.
4. The first insulating part is made of ceramic. A plasma supply device according to any one of claims 1 to 3.
5. The cylindrical portion further comprises a cylindrical protective layer that covers the inner circumferential surface of the cylindrical portion. A plasma supply device according to any one of claims 1 to 3.
6. The cylindrical protective layer is made of ceramic. The plasma supply device according to feature 5.