PLASMA CHEMICAL VAPOR DEPOSITION DEVICE
20170229292 · 2017-08-10
Assignee
Inventors
- Yoji SATO (Kasugai-shi, JP)
- Takayasu SATO (Takahama-shi, JP)
- Kazutaka TACHIBANA (Nagoya-shi, JP)
- Hiromichi NAKATA (Toyota-shi, JP)
Cpc classification
International classification
Abstract
A plasma chemical vapor deposition device includes an adhesion suppressing sheet suppressing a processing gas from adhering to an inner wall of a reactor. The adhesion suppressing sheet is arranged between a placement position of a workpiece and the inner wall of the reactor. The adhesion suppressing sheet is a fabric that includes first fiber bundles and second fiber bundles that extend in directions different from each other. In the first fiber bundles, front side portions and rear side portions are alternately arranged in a first direction. In the second fiber bundles, front side portions and rear side portions are alternately arranged in a second direction.
Claims
1. A plasma chemical vapor deposition device configured to form a film on a workpiece placed in a reactor by converting a processing gas supplied into the reactor into plasma and decomposing the gas, comprising, an adhesion suppressing sheet suppressing the processing gas from adhering to an inner wall of the reactor, wherein the adhesion suppressing sheet is arranged between a placement position of the workpiece in the reactor and the inner wall of the reactor, the adhesion suppressing sheet is a fabric that includes a plurality of first fiber bundles and a plurality of second fiber bundles, the plurality of first fiber bundles extending in a first direction and each including a plurality of fibers, and the plurality of second fiber bundles extending in a second direction different from the first direction and each including a plurality of fibers, and in the adhesion suppressing sheet, when a surface on a side of the placement position is defined as a front surface and a surface on a side of the inner wall of the reactor is defined as a rear surface, in each of the plurality of first fiber bundles, front side portions that are positioned on a front side relative to the second fiber bundles and are exposed at the front surface, and rear side portions that are positioned on a rear side relative to the second fiber bundles and are not exposed at the front surface are alternately arranged in the first direction, and in each of the plurality of second fiber bundles, front side portions that are positioned on a front side relative to the first fiber bundles and are exposed at the front surface, and rear side portions that are positioned on a rear side relative to the first fiber bundles and are not exposed at the front surface are alternately arranged in the second direction.
2. The plasma chemical vapor deposition device according to claim 1, wherein each of the plurality of first fiber bundles and the plurality of second fiber bundles is obtained by arranging a plurality of fibers in parallel.
3. The plasma chemical vapor deposition device according to claim 1, wherein at least one of the first fiber bundles and the second fiber bundles has a width dimension that is greater than a thickness dimension, when a direction in which the plurality of fibers of the at least one of the first fiber bundles and the second fiber bundles are arranged is defined as a width direction and a direction perpendicular to both an extending direction and the width direction is defined as a thickness direction among directions perpendicular to the extending direction.
4. The plasma chemical vapor deposition device according to claim 3, wherein each of the plurality of first fiber bundles has a width that is 5 times a thickness or more and each of the plurality of second fiber bundles has a width that is 5 times a thickness or more.
5. The plasma chemical vapor deposition device according to claim 1, wherein the adhesion suppressing sheet has a tubular shape, and the adhesion suppressing sheet is arranged to surround the placement position.
6. The plasma chemical vapor deposition device according to claim 1, wherein the film formed on the workpiece is a diamond-like carbon film and the fibers of the first fiber bundles and the fibers of the second fiber bundles are carbon fibers.
7. The plasma chemical vapor deposition device according to claim 6, wherein in the adhesion suppressing sheet, when a ratio of carbon atoms having a diamond structure among carbon atoms included in the diamond-like carbon film is defined as a reference ratio, a ratio of carbon atoms having a diamond structure among carbon atoms included in the carbon fibers is equal to the reference ratio.
8. The plasma chemical vapor deposition device according to claim 1, wherein a fixing member fixed to the inner wall of the reactor is arranged between the inner wall of the reactor and the adhesion suppressing sheet, and a plurality of parts of the adhesion suppressing sheet are bound to the fixing member by binding members.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
[0026]
[0027]
[0028]
[0029]
[0030]
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[0032]
[0033]
[0034]
[0035]
DETAILED DESCRIPTION OF EMBODIMENTS
[0036] Hereinafter, an embodiment of a plasma chemical vapor deposition device will be described with reference to
[0037] In addition, in the PCVD device 11, an elongated first conductor 20 and a tubular second conductor 30 that is positioned further outward than the first conductor 20 and that is disposed coaxially with the first conductor 20 are provided. A space is formed between an inner surface 30a of the second conductor 30 and a side surface 20a of the first conductor 20 that faces the inner surface 30a. Therefore, a sealing member 41 for regulating inflow of outside air into the reactor 12 is disposed between the second conductor 30 and the first conductor 20. An inner circumferential surface of the sealing member 41 comes in close contact with the side surface 20a of the first conductor 20 and an outer circumferential surface of the sealing member 41 comes in close contact with the inner surface 30a of the second conductor 30. Also, the sealing member 41 is made of an insulating material through which microwaves can pass.
[0038] A tip of the first conductor 20 is positioned in the reactor 12 and the workpiece W is placed thereon. That is, the tip of the first conductor 20 positioned in the reactor 12 serves as a support portion 21 that directly supports the workpiece W.
[0039] The second conductor 30 is grounded to the ground, and a potential of the second conductor 30 is “0 V.” A tip of the second conductor 30 enters the reactor 12 through an aperture 121 that is formed in a side wall of the reactor 12.
[0040] In addition, the PCVD device 11 includes a high frequency output device 45 configured to output microwaves and a DC power supply 46 configured to output a DC voltage. In the high frequency output device 45, an output unit 451 configured to output microwaves is provided. The output unit 451 passes through a through hole 31 provided in the second conductor 30, that is, is connected to the first conductor 20 without being in contact with the second conductor 30. Therefore, microwaves output from the high frequency output device 45 flow in the side surface 20a of the first conductor 20. In this case, microwaves flowing in the side surface 20a of the first conductor 20 are suppressed from leaking to the outside of the device by the second conductor 30.
[0041] In addition, the DC power supply 46 is connected to the first conductor 20 and a DC voltage from the DC power supply 46 is supplied to the first conductor 20. Therefore, a direct current flowing in the first conductor 20 also flows in the workpiece W that is supported on the first conductor 20. Accordingly, the workpiece W is charged with negative charges.
[0042] Therefore, when a film is formed on the workpiece W, microwaves are output from the high frequency output device 45 while such a direct current flows in the workpiece W. Accordingly, microwaves are propagated to a surface of the workpiece W charged with negative charges, and a hydrocarbon gas is converted into plasma and decomposed in the vicinity of the workpiece W in the reactor 12. As a result, on the surface of the workpiece W, a diamond-like carbon film (hereinafter referred to as a “DLC film”) that is a hydrocarbon-gas-based film is formed.
[0043] Next, a configuration for suppressing a hydrocarbon gas from adhering to an inner wall of the reactor 12 will be described. As shown in
[0044] In addition, a tubular adhesion suppressing sheet 60 is arranged between the tubular portion 51 of the net member 50 and the placement position PA of the workpiece W. That is, the adhesion suppressing sheet 60 is disposed to surround the placement position PA.
[0045] As shown in
[0046] Next, a configuration of the adhesion suppressing sheet 60 will be described with reference to
[0047] As shown in
[0048] Note that the DLC film formed on the workpiece W is a film in which carbon atoms having a diamond structure (referred to as an “sp3 structure”) and carbon atoms having a carbon structure (referred to as an “sp2 structure”) are mixed. The hardness of the DLC film increases as a ratio of carbon atoms having a diamond structure among carbon atoms included in the film increases. In addition, a composition of the adhesive substance deposited on the adhesion suppressing sheet 60 when the DLC film is formed on the workpiece W can be considered to be the same as a composition of the DLC film. Here, a ratio of carbon atoms having a diamond structure among carbon atoms included in the DLC film formed on the workpiece W is defined as a reference ratio. Therefore, in order to set a structure of the fiber bundles 61 and 62 to be similar to a structure of the adhesive substance deposited on the fiber bundles 61 and 62, as the carbon fiber 65 included in the fiber bundles 61 and 62, a carbon fiber in which a ratio of carbon atoms having a diamond structure among carbon atoms included in the carbon fiber 65 is equal to the reference ratio is used. Note that, when it is described that the ratio of carbon atoms having a diamond structure among carbon atoms is “equal,” it includes values that are the same and values considered to be the same in consideration of the hardness and the like.
[0049] As shown in
[0050] Next, operations performed when the DLC film is formed on the workpiece W placed in the reactor 12 will be described with reference to
[0051] On the other hand, adhesion of a gas to the rear side portions 612 of the first fiber bundles 61 is suppressed by the second fiber bundles 62, and adhesion of a gas to the rear side portions 622 of the second fiber bundles 62 is suppressed by the first fiber bundles 61. Therefore, the adhesive substance D is not deposited on the rear side portions 612 of the first fiber bundles 61 or the rear side portions 622 of the second fiber bundles 62. That is, in this embodiment, the adhesive substance D is not deposited on the entire first fiber bundles 61 and second fiber bundles 62, but a plurality of regions on which the adhesive substance D is deposited are positioned with intervals therebetween.
[0052] When the adhesive substance D is deposited on the front side portions 611 and 621, a force is applied to the front side portions 611 and 621 by the adhesive substance D. Such a force from the adhesive substance D increases as an amount of the adhesive substance D deposited on the front side portions 611 and 621 increases. That is, as indicated by arrows in
[0053] According to the configuration and operation described above, the following effects can be obtained. (1) In the fiber bundles 61 and 62, in order to deform the front side portions 611 and 621 according to a force from the adhesive substance D deposited on the front side portions 611 and 621, it is also necessary to deform the rear side portions 612 and 622 with the force. Therefore, an amount of deformation of the front side portions 611 and 621 is less likely to increase. Accordingly, it is possible to suppress the adhesive substance D deposited on the front side portions 611 and 621 from being damaged due to an increased amount of deformation of the front side portions 611 and 621. Therefore, it is possible to suppress flakes from being generated in the reactor 12 and suppress flakes from adhering to the workpiece W placed in the reactor 12.
[0054] (2) In this embodiment, since the fiber bundles 61 and 62 are obtained by aligning the plurality of carbon fibers 65, the fiber bundles have higher flexibility than fiber bundles of yarns obtained by twisting a plurality of carbon fibers. Therefore, an amount of deformation of the front side portions 611 and 621 on which the adhesive substance D is deposited is suppressed from becoming too small, and the internal stress of the adhesive substance D deposited on the front side portions 611 and 621 is less likely to increase. Therefore, it is possible to suppress the adhesive substance D from being exfoliated from the front side portions 611 and 621 due to the increased internal stress of the adhesive substance D.
[0055] (3) In addition, since the width of each of the first fiber bundles 61 and the second fiber bundles 62 is 5 times the thickness or more, it is possible to sufficiently ensure lengths of the rear side portions 622 of the second fiber bundles 62 in the second direction X2, and it is possible to sufficiently ensure lengths of the rear side portions 612 of the first fiber bundles 61 in the first direction X1. Therefore, the stress generated in the fiber bundles 61 and 62 according to deformation of the front side portions 611 and 621 is dispersed in the long rear side portions 612 and 622. As a result, deformation of the rear side portions 612 and 622 is suppressed, and deformation of the front side portions 611 and 621 is also suppressed as a result. Therefore, excessive deformation of the front side portions 611 and 621 of the fiber bundles 61 and 62 is suppressed, and accordingly, it is possible to further improve an effect of suppressing the adhesive substance D deposited on the front side portions 611 and 621 from being damaged due to deformation of the front side portions 611 and 621.
[0056] (4) When widths of any one group of the first fiber bundles 61 and the second fiber bundles 62 are narrower than widths of the other fiber bundles, lengths of the rear side portions of the other fiber bundles in an extending direction are short, and the stress generated in the other fiber bundles due to deformation of the front side portions is not easily dispersed in the rear side portions. On the other hand, in this case, since lengths of the rear side portions of the one group of the fiber bundles in the extending direction are long, the stress generated in the one group of the fiber bundles due to deformation of the front side portions is easily dispersed in the rear side portions. Therefore, while the front side portions of the one group of the fiber bundles are not deformed much, an amount of deformation of the front side portions of the other fiber bundles may be excessive. In this case, since the amount of deformation of the front side portions of the other fiber bundles is excessive, it is necessary to replace the adhesion suppressing sheet 60 even if the adhesive substance D is not yet exfoliated from the one group of the fiber bundles. In this regard, in this embodiment, since widths of the first fiber bundles 61 and widths of the second fiber bundles 62 are equal to each other, it is possible to suppress a replacement frequency of the adhesion suppressing sheet 60 from increasing due to small widths of one of the groups of fiber bundles.
[0057] (5) Since the tubular adhesion suppressing sheet 60 is arranged to surround the placement position PA of the workpiece W, plasma generated in the reactor 12 can be surrounded by the adhesion suppressing sheet 60. Therefore, a processing gas that does not adhere to the workpiece W can easily adhere to an inner surface of the adhesion suppressing sheet 60, that is, the front side portions 611 and 621 of the fiber bundles 61 and 62. Therefore, it is possible to appropriately suppress a processing gas from adhering to the inner wall of the reactor 12.
[0058] (6) Since both the adhesive substance D deposited on the front side portions 611 and 621 of the fiber bundles 61 and 62 and the fiber bundles 61 and 62 are carbon-based substances, an adhesion force of the adhesive substance D on the fiber bundles 61 and 62 increases. Therefore, even if the internal stress of the adhesive substance D increases, the adhesive substance D is not easily exfoliated from the fiber bundles 61 and 62.
[0059] (7) A ratio of carbon atoms having a diamond structure among carbon atoms included in the carbon fiber 65 of the fiber bundles 61 and 62 is equal to the reference ratio. Therefore, the adhesive substance D is deposited on the fiber bundles 61 and 62 having a structure similar to the structure of the adhesive substance D. Therefore, it is possible to further increase an adhesion force of the adhesive substance D on the fiber bundles 61 and 62. In addition, since the structure of the adhesive substance D is similar to the structure of the adhesion suppressing sheet 60, a coefficient of thermal expansion of the adhesive substance D is substantially equal to a coefficient of thermal expansion of the adhesion suppressing sheet 60. Accordingly, when heat is applied to the adhesion suppressing sheet 60 and the adhesion suppressing sheet 60 and the adhesive substance D thermally expand, an amount of thermal expansion of the adhesive substance D becomes substantially equal to an amount of thermal expansion of the adhesion suppressing sheet 60. Therefore, it is possible to suppress the adhesive substance D from being exfoliated from the adhesion suppressing sheet 60 even if the adhesion suppressing sheet 60 thermally expands.
[0060] (8) A plurality of parts of the adhesion suppressing sheet 60 are bound to the net member 50 fixed to the inner wall of the reactor 12 by the binding thread material 56. Therefore, deformation of the fiber bundles 61 and 62 due to deposition of the adhesive substance D on the front side portions 611 and 621 is not easily inhibited in parts other than the parts that are bound by the binding thread material 56 in the adhesion suppressing sheet 60. Further, even if the fiber bundles 61 and 62 are deformed due to deposition of the adhesive substance D, since the net member 50 fixed to the inner wall of the reactor 12 is not deformed, the adhesion suppressing sheet 60 does not easily approach the placement position PA. Therefore, it is possible to suppress interference between the adhesion suppressing sheet 60 and plasma while suppressing inhibition of deformation of the fiber bundles 61 and 62 due to deposition of the adhesive substance D.
[0061] (9) In addition, since the adhesion suppressing sheet 60 is attached to the net member 50 by the plurality of binding thread materials 56, when the bolt 55 is removed to release the net member 50 fixed to the inner wall of the reactor 12, it is possible to easily detach the adhesion suppressing sheet 60 from the inside of the reactor 12 together with the net member 50. Therefore, compared to when the adhesion suppressing sheet 60 is directly attached to the inner wall of the reactor 12 by the plurality of binding thread materials 56, the adhesion suppressing sheet 60 can be easily replaced.
[0062] (10) In addition, even if the adhesive substance D is deposited in this manner, since it is possible to suppress the adhesion suppressing sheet 60 from approaching the placement position PA, it is not necessary to dispose the adhesion suppressing sheet 60 far apart from the placement position PA in order to suppress interference between the adhesion suppressing sheet 60 and plasma, and a small reactor can be used as the reactor 12. That is, it is possible to reduce the size of the PCVD device 11.
[0063] Also, the embodiment may be changed to other embodiments to be described below. As a fixing member to which the adhesion suppressing sheet 60 is bound by the binding thread material 56, a member other than the net member 50 may be used as long as it has sufficient rigidity that deformation does not occur even if a force based on deformation of the fiber bundles 61 and 62 due to deposition of the adhesive substance D is applied by the adhesion suppressing sheet 60. For example, a cylindrical body formed of a plate of a metal such as aluminum can be used as the fixing member.
[0064] The adhesion suppressing sheet 60 may be directly attached to the inner wall of the reactor 12 without the fixing member. The fiber bundles 61 and 62 may include a carbon fiber whose ratio of carbon atoms having a diamond structure is different from the reference ratio. In this case also, it is possible to obtain the same effects as in (1) to (6) and (8) to (10). Also, in order to suppress exfoliation of the adhesive substance D, it is desirable that a ratio of carbon atoms having a diamond structure in the fiber bundles 61 and 62 be as close to the reference ratio as possible.
[0065] The fiber bundles 61 and 62 may include fibers other than the carbon fibers as long as they are deformed by a force from the deposited adhesive substance D. In this case also, it is possible to obtain the same effects as in (1) to (5) and (8) to (10).
[0066] The adhesion suppressing sheet may not have a tubular shape. In this case also, when a plurality of adhesion suppressing sheets are disposed to surround the placement position PA, it is possible to suppress the adhesive substance D from being deposited on the inner wall of the reactor 12.
[0067] Fiber bundles other than the fiber bundles obtained by arranging pluralities of fibers in parallel may be used as long as they are deformed by a force from the deposited adhesive substance D. As an example of such fiber bundles, a yarn obtained by twisting pluralities of fibers can be used.
[0068] In the embodiment, the adhesion suppressing sheet 60 is obtained by plain weaving of the first fiber bundles 61 and the second fiber bundles 62 whose widths are the same. However, for example, as shown in
[0069] In addition, on the contrary to
[0070] In addition, as shown in
[0071] The widths of the fiber bundles 61 and 62 may be less than 5 times the thicknesses of the fiber bundles 61 and 62 as long as the adhesive substance D is not exfoliated from the front side portions 611 and 621 due to deformation of the front side portions 611 and 621 according to a force from the adhesive substance D deposited on the front side portions 611 and 621.
[0072] In the embodiment, the adhesion suppressing sheet 60 may include the first fiber bundles 61 and the second fiber bundles 62 that extend in directions perpendicular to each other. However, as long as the front side portions 611 and the rear side portions 612 are alternately arranged in the first fiber bundles 61, and the front side portions 621 and the rear side portions 622 are alternately arranged in the second fiber bundles 62, an adhesion suppressing sheet including weaves of the first fiber bundles 61 and the second fiber bundles 62 that form an angle that is not a right angle may be placed in the reactor 12.
[0073] The PCVD device 11 in which the adhesion suppressing sheet 60 is placed in the reactor 12 may be embodied as a device configured to form a film other than the DLC film on the workpiece W.