Plasma supply device

Abstract

A plasma supply device 10A according to the present invention comprises: a first electrode that includes a cylindrical part 12 and a columnar plug part 11 which is inserted from an end part of the cylindrical part 12 on one side; a first insulating part 13A that surrounds an outer circumferential surface 12b of an end part of the cylindrical part 12 on the other side; a second insulating part 14 that surrounds the outer circumferential surface of a portion other than the end part of the cylindrical part 12 on the other side; and an exterior part 15, as a second electrode, that surrounds the first insulating part 13A and the second insulating part 14. The cylindrical part 12 is longer than the columnar plug part 11. Moreover, the value calculated by the expression "L / Φ1", where Φ1 is the inner diameter of a portion of the space within the cylindrical part 12 not occupied by the columnar plug 11, and L is the length of said portion, is 4 or less. According to the present invention, it is possible to prevent electrode wear at a low cost.

Description

Plasma supply device

[0001] The present invention relates to a plasma supply device that supplies plasma toward a space that requires plasma.

[0002] Conventionally, a plasma supply device including a first electrode having a cylindrical shape, a second electrode located at one end portion of the first electrode, and a gas introduction path for introducing a gas to be plasmaized is known (see, for example, 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 portion of the first electrode toward the space that requires plasma.

[0003] Japanese Patent No. 7319928 Japanese Patent Publication No. 62-56640

[0004] In the above conventional plasma supply device, the other end portion of the first electrode, which is the plasma outlet, may be damaged by plasma and consumed. 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.

[0006] In order to solve the above problems, the plasma supply device according to the present invention includes a first electrode including a cylindrical portion and a columnar plug portion inserted from one end portion of the cylindrical portion, a first insulating portion surrounding the outer peripheral surface of the other end portion of the cylindrical portion, a second insulating portion surrounding the outer peripheral surface of a portion other than the other end portion of the cylindrical portion, and an exterior portion as a second electrode surrounding the first insulating portion and the second insulating portion. The cylindrical portion is longer than the columnar plug portion, and when the inner diameter of the portion of the space inside the cylindrical portion that is not occupied by the columnar plug portion is Φ and the 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.

[0010] According to the present invention, it is possible to provide a plasma supply device that can reduce electrode wear at a low cost.

[0011] This is a schematic end view showing a plasma supply device according to the first embodiment of the present invention. This is a schematic end view showing a plasma supply device according to the second embodiment of the present invention. This is a schematic end view showing a plasma supply device according to the third embodiment of the present invention. This is a graph showing measurement results of the plasma supply device according to the present invention. This is a graph showing another measurement result of the plasma supply device according to the present 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 that surrounds the outer circumferential surface of the cylindrical portion 12 other than the other end. In this embodiment, the second insulating portion 13 is made of PEEK resin.

[0018] The exterior portion 15 mainly includes a portion surrounding the second insulating portion 14, a portion (constricted portion) 15a that surrounds the first insulating portion 13A at a position closer to the plasma outlet than the portion said, and a portion (flange portion) 15b that surrounds the first insulating portion 13A at a position even closer to the plasma outlet than the constricted portion 15a. In this embodiment, the exterior portion 15 is made of aluminum.

[0019] The plasma supply device 10A further includes the aforementioned terminal section 16. The terminal section 16 is electrically connected to the central conductor and cylindrical plug section 11 of the coaxial cable extending from the high-frequency power supply RF. The outer casing 15 is electrically connected to the outer conductor (GND) of the coaxial cable when the terminal section 16 is connected to the central conductor.

[0020] The plasma supply device 10A generates plasma in the portion of the space within 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 via the other end of the cylindrical portion 12. Hereinafter, this portion will be referred to as the "plasma generation space". As shown in Figure 1, the plasma generation space has a diameter of Φ1 and a length of L. In this embodiment, the diameter Φ1 is equal to the diameter Φ2.

[0021] The plasma supply device 10A supplies the gas to be plasmaized (in this embodiment, NF ３ The device further includes a gas inlet 17 into which gas is injected, and gas flow paths 18 and 19. The gas inlet 17 and the gas flow paths 18 and 19 are in communication with each other. The gas flow path 19 is also in communication with the plasma generation space through a small gap between the outer surface of the cylindrical plug portion 11 and the inner surface of the cylindrical portion 12.

[0022] The plasma supply device 10A further includes a cooling medium channel 20. By passing a cooling medium (water in this embodiment) through the cooling medium channel 20, the cylindrical portion 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 the 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 first to seventh 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 one hour and the decomposition rate after supplying plasma for two hours for each device will be described. In all measurements, NF injected into the gas inlet 17 ３ The gas flow rate 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 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 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 Embodiment] 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 Embodiment] The plasma supply device according to this embodiment is the plasma supply device 10C according to the third embodiment, wherein 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 Embodiment] The plasma supply device according to this embodiment is the plasma supply device 10C according to the third embodiment, wherein 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 according to the first to fourth examples and comparative examples.

[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 about ±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 devices according to the first and fifth embodiments.

[0041] This result indicates that the plasma supply device according to the fifth embodiment in which the cylindrical protective layer 21 is provided on the inner peripheral surface of the cylindrical portion 12 has a lower consumption amount than the plasma supply device according to the first embodiment in which the cylindrical protective layer 21 is not provided. Note that it is considered that there is no significant difference in the decomposition rate.

[0042] Table 3 and FIG. 5 show the measurement results for the plasma supply devices according to the fifth to seventh embodiments.

[0043] This result indicates that the plasma supply devices according to the sixth embodiment in which the plasma outlet diameter Φ2 is 10 mm and the seventh embodiment in which it is 6 mm have a lower consumption amount than the plasma supply device according to the fifth embodiment in which the plasma outlet diameter Φ2 is 12 mm. In other words, this result indicates that by narrowing the plasma outlet by the first insulating portion 13C, the consumption amount is reduced. Note that it is considered that there is no significant difference in the decomposition rate.

[0044] As described above, the plasma supply devices according to the first to third embodiments of the present invention have been described, but the configuration of the present invention is not limited to these.

[0045] For example, the first insulating portion 13A may not include an end face covering portion that covers the end face 12a of the other end portion of the cylindrical portion 12.

[0046] Further, the cylindrical protective layer 21 may have a convex portion extending toward the axis of the cylindrical portion 12. In other words, the plasma generation space may be partially reduced in diameter. According to this configuration, it is considered that the same effect as when the plasma outlet is narrowed by the first insulating portion 13C can be obtained.

[0047] 10A, 10B, 10C Plasma supply device 11 Cylindrical section (first electrode) 12 Cylindrical plug section (first electrode) 13A, 13C First insulating section 14 Second insulating section 15 Outer casing (second 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 plasma supply device comprising: 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 the length is L, the value calculated by the formula "L / Φ" is 4 or less.

2. The plasma supply apparatus according to claim 1, characterized in that the first insulating portion includes an end face covering portion that covers the end face of the other end of the cylindrical portion.

3. The plasma supply apparatus according to claim 2, characterized in that the first insulating portion further includes an extension portion extending from the end face covering portion toward the axis of the cylindrical portion.

4. The plasma supply apparatus according to claim 3, characterized in that the first insulating part is made of ceramic.

5. The plasma supply device according to claim 1, further comprising a cylindrical protective layer covering the inner circumferential surface of the cylindrical portion.

6. The plasma supply apparatus according to claim 5, characterized in that the cylindrical protective layer is made of ceramic.

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