JP6580829B2 - Plasma CVD deposition system - Google Patents

Description

  The present invention relates to a plasma CVD film forming apparatus.

  Conventionally, a plasma CVD film forming apparatus has been used to continuously form a film such as a silicon oxide film on the surface of a thin belt-like substrate such as a plastic film.

  As described in Patent Document 1, the plasma CVD film forming apparatus includes a vacuum chamber filled with a raw material gas serving as a film raw material, and a pair of metal film forming rollers disposed in the vacuum chamber. And a power source in which electrodes are respectively connected to the pair of film forming rollers, and a magnetic field generating unit provided inside each of the pair of film forming rollers.

  In the case where a film is continuously formed on the surface of a belt-like base material using this film forming apparatus, the belt-like base material is sent out in a state where the belt-like base material is wound around mutually facing portions of a pair of film forming rollers. At this time, the magnetic field generating means generates a magnetic field in the space between the pair of film forming rollers. The power supply applies a high-frequency AC voltage at a high voltage between the pair of film forming rollers. Thereby, plasma is generated in the region of the magnetic field between the pair of film forming rollers. The molecules of the source gas inside the vacuum chamber are decomposed by the generated plasma energy and adhere to the surface of the base material, whereby a film is continuously formed on the surface of the base material. In this way, a film is continuously formed on the surface of the substrate by plasma CVD.

  As described above, during the film forming operation, the belt-like base material is wound around the opposing portions of the pair of film forming rollers. However, both ends of each film-forming roller are exposed without the substrate being wound thereon. Therefore, the plasma generated between the pair of film forming rollers may cause a film to be formed at both ends of each exposed film forming roller.

  Therefore, in order to prevent film formation at both ends of these film forming rollers, in the film forming apparatus described in Patent Document 1, a shielding member that covers both ends of each film forming roller between the pair of film forming rollers. Is provided. The shielding member has a curved shape along the circumferential direction of the end surface of the film forming roller.

  The shielding member covers both ends of each film forming roller, thereby suppressing the occurrence of abnormal discharge at the both ends. Thereby, it is prevented that a film is formed on both ends of the film forming roller by the discharge.

JP 2011-84780 A

  In the film forming apparatus described in Patent Document 1, a shielding member that covers both ends of each film forming roller is provided between the pair of film forming rollers in order to prevent film formation at both ends of the film forming roller. ing.

  In this configuration, in the axial direction of the film forming roller, the portion of the metal outer peripheral surface of the film forming roller in the range where film forming is performed has the surface of the film forming roller as the surface of the film forming roller. Covered with However, other portions, that is, portions where the base material is not wound are exposed to the outside because they are not in contact with the base material. As described above, in the portion of the metal film forming roller that is exposed to the outside, abnormal discharge occurs due to the potential difference between the exposed portion and the surrounding portion (for example, the inner wall of the vacuum chamber). May occur. Therefore, there is a possibility that the film forming operation cannot be continued.

  The present invention has been made in view of the circumstances as described above, and prevents the occurrence of abnormal discharge in a portion where the substrate is not wound in a range where film formation is performed in the axial direction of the film formation roller. An object is to provide a plasma CVD film forming apparatus.

The plasma CVD film forming apparatus of the present invention includes a vacuum chamber and a film forming roller rotatably attached to the inside of the vacuum chamber, wherein a belt-like base material is part of the entire circumference of the film forming roller. A metal film forming roller to be wound, a magnetic field generating unit that is disposed inside the film forming roller and generates a magnetic field outside a portion of the film forming roller on which the substrate is wound, and the film forming roller A power source for applying an AC voltage for generating plasma in the region of the magnetic field to the film forming roller, and a portion of the film forming roller with respect to a portion of the film forming roller on which the substrate is wound. A cover that covers a non-contact portion that is not in contact with the base material that is located on the opposite side across the rotating shaft, and is disposed adjacent to the film forming roller, and the interior of the vacuum chamber is within the region of the magnetic field Generated The plasma is present, and comprises a film forming area where the base material is formed using the plasma and a partition wall which is divided into a non-film forming area where the base material is not formed, The pressure in the non-film-forming area is set to be higher than the pressure in the film-forming area, and the film-forming roller is arranged in the portion arranged in the film-forming area and in the non-film-forming area has a portion, the cover includes a metallic main body, made of insulation material, and an insulating portion for covering a part facing the film-forming roller in the main body, the cover, The film forming roller is disposed only in the non-film forming area higher than the pressure in the film forming area so as to cover a non-contact portion that is not in contact with the base material.

When performing plasma CVD, in a state where an AC voltage for generating plasma is applied to the film forming roller, the base material of the film forming roller is within the range where film forming is performed in the axial direction of the film forming roller. Not only the part that is wound and is in contact with the substrate, but also the part that is not in contact with the substrate that is located on the opposite side of the rotation axis of the film forming roller with respect to the part where the substrate is wound. The portion on the back side of the film roller is also at a potential capable of generating plasma. For this reason, abnormal discharge is likely to occur in the portion on the back side of the film forming roller that is not in contact with the base material. Therefore, in the present invention, the cover is a non-contact portion that is not in contact with the base material that is located on the opposite side of the film forming roller with respect to the portion around which the base material is wound. Covering. As a result, not only the part of the film forming roller that is in contact with the base material but also the non-contact part that is not in contact with the base material that is the back side of the part is covered with the cover. It is possible to prevent the occurrence of abnormal discharge in the portion.

In the above configuration, the insulating portion that covers the portion of the main body of the cover that faces the film formation roller insulates the film formation roller from the surrounding objects, so that the film formation roller and the surrounding objects are separated from each other. It is possible to prevent the occurrence of abnormal discharge. Thereby, it is possible to prevent the film formation on the film forming roller and the surrounding objects.

Furthermore, according to said structure, the part which opposes the film-forming roller among the metal main-body parts in a cover is covered with the insulating part which consists of insulating materials. Therefore, although the main body is made of metal, it is possible to prevent the occurrence of abnormal discharge between the main body and the film forming roller, thereby preventing the formation of a film on the main body.

In addition, according to the above configuration, since the pressure in the non-film formation area is set to be higher than the pressure in the film formation area, a gas serving as a raw material for film formation is formed in the film formation area. When fed, this gas can be prevented from diffusing from the film formation area to the non-film formation area through the gap between the film formation roller and the partition wall. In addition, if the pressure in the non-film formation area is high, discharge tends to occur in the portion of the film formation roller arranged in the non-film formation area . Since it is arranged only in the non-film formation area that is higher than the pressure in the film formation area so as to cover the non-contact part that is not in contact with the substrate, it prevents the occurrence of abnormal discharge in the non-contact part It is possible to prevent the occurrence.

  As described above, according to the plasma CVD film forming apparatus of the present invention, the film forming roller is positioned on the opposite side with respect to the portion around which the substrate is wound with respect to the rotation axis of the film forming roller. It is possible to prevent the occurrence of abnormal discharge in the portion, that is, the portion where the substrate is not wound.

It is a front view of the state which removed the front surface of the vacuum chamber which shows the whole structure of the plasma CVD film-forming apparatus which concerns on embodiment of this invention. FIG. 2 is an enlarged front view showing the arrangement of a cover for the film forming roller of FIG. 1. FIG. 2 is an enlarged plan view around a pair of film forming rollers of the plasma CVD film forming apparatus of FIG. 1. FIG. 2 is an enlarged perspective view showing an arrangement of a cover for the film forming roller of FIG. 1. It is an enlarged plan view of a pair of film forming rollers showing the structure of a plasma CVD film forming apparatus provided with a cover extending over the entire length of the film forming roller according to a modification of the present invention. The enlarged plan view of a periphery of a pair of film forming rollers showing the structure of a plasma CVD film forming apparatus provided with a roller insulating portion covering a range where film forming in the axial direction is performed in a film forming roller according to another modification of the present invention. It is. It is an enlarged front view which shows arrangement | positioning of the roller insulation part and cover with respect to the film-forming roller of FIG. FIG. 7 is an exploded plan view in a state where an end cap is removed from an end portion of the film forming roller of FIG. 6.

  Hereinafter, embodiments of the plasma CVD film forming apparatus of the present invention will be described in more detail with reference to the drawings.

  A plasma CVD film forming apparatus 10 (hereinafter referred to as a film forming apparatus 10) shown in FIGS. 1 to 4 is an apparatus that continuously forms a thin film on the surface of a strip-shaped substrate A by plasma CVD. The film forming apparatus 10 includes a vacuum chamber 1, a pair of film forming rollers 2 rotatably attached to the inside of the vacuum chamber, a magnet 3 disposed inside each film forming roller 2, and a pair of film forming rollers. 2, a high frequency power source 4 for applying a high frequency AC voltage, a plurality of guide rollers 5, a partition wall 6 for partitioning the inside of the vacuum chamber 1, and a portion 2a of the film forming roller 2 opposite to the portion 2a around which the substrate A is wound. And a cover 9 that covers the portion 2b that is not in contact with the substrate A.

  The vacuum chamber 1 is a hollow casing and has an exhaust port 15 connected to an exhaust means such as a vacuum pump (not shown).

  The internal space of the vacuum chamber 1 is divided into two spaces, that is, a low pressure chamber 7 and a high pressure chamber 8 by the film forming roller 2 and the partition wall 6 adjacent thereto. The low-pressure chamber 7 is a film formation area where the substrate A is formed on the surface of the film formation roller 2. The high-pressure chamber 8 is a non-film formation area where the base material A is not formed.

  The low pressure chamber 7 communicates with the exhaust port 15 and is decompressed to a vacuum state or a low pressure state. The low pressure chamber 7 is provided with a source gas supply port 12 and an oxygen gas supply port 13. The raw material gas G1 that is the material of the film is supplied to the low pressure chamber 7 through the raw material gas supply port 12. The oxygen gas OX is supplied to the low pressure chamber 7 through the oxygen gas supply port 13. The high-pressure chamber 8 is provided with an oxygen gas supply port 14, and oxygen gas OX is supplied through the oxygen gas supply port 14. The high pressure chamber 8 is maintained at a higher pressure than the inside of the low pressure chamber 7.

  The pair of film forming rollers 2 are rollers made of a metal such as stainless steel. The pair of film forming rollers 2 is rotatably mounted inside the vacuum chamber 1. That is, both end portions of the rotating shaft 2 c of each film forming roller 2 are rotatably supported by a pair of opposing side walls of the vacuum chamber 1. Opposing portions 2 a of the pair of film forming rollers 2 are inserted into the opening 6 a of the partition wall 6 and accommodated in the low pressure chamber 7.

  The belt-like substrate A is wound around the mutually opposing portions 2 a of the entire circumference of the pair of film forming rollers 2.

  Of the entire circumference of the pair of film forming rollers 2, a part 2 b around which the substrate A is not wound (that is, a part on the back side) 2 b is located in the high pressure chamber 8 of the vacuum chamber 1.

  The temperature of each film forming roller 2 may be adjusted within a range of about −20 to 200 ° C. Therefore, the film-forming roller 2 needs to have thermal characteristics that do not change or break in these temperature ranges. The material of the film forming roller 2 is preferably a metal material having a low magnetic permeability such as stainless steel so that the magnetic field generated by the magnet 3 can be easily propagated.

  In the region 2e where the magnet 3 is arranged in the axial direction of each film forming roller 2, the surface of the film forming roller 2 is not covered with the insulating portion 19 and thus is exposed. On the other hand, the range around the arrangement area 2e of the magnet 3 is covered with an insulating portion 19 made of an insulating material. The insulating part 19 covers regions on both sides of the film forming roller 2. End portions 2 d on both sides of the film forming roller 2 are covered with end caps 11. The surface of the end cap 11 is covered with an insulating portion 20 made of an insulating material.

  The magnets 3 are disposed inside the film forming roller 2, specifically, inside the portions 2 a of the pair of film forming rollers 2 facing each other. The magnet 3 generates a magnetic field between the pair of film forming rollers 2 and outside the portion 2a around which the base material A is wound. The magnet 3 is a concept included in the magnetic field generation unit of the present invention, and is composed of, for example, a permanent magnet (neodymium, samarium cobalt, ferrite, or the like).

  The high frequency power source 4 is connected to each of the pair of film forming rollers 2. The high-frequency power source 4 applies a high-frequency AC voltage for generating the plasma P in the magnetic field region between the pair of film forming rollers 2. As a result, electric discharge is generated between the pair of film forming rollers 2 in the low pressure chamber 7, and the raw material gas G <b> 1 is in a plasma state in the magnetic field region near the magnet 3 to generate plasma P. In other words, the low pressure chamber 7 functions as a film formation area in which the plasma P generated in the magnetic field region exists and the substrate A is formed using the plasma P.

  The voltage applied to the pair of film forming rollers 2 from the high-frequency power source 4 is a high-frequency (for example, about 10 to several hundred kHz, preferably about several tens kHz) whose average voltage is negative with respect to the potential of the vacuum chamber 1. A voltage with a peak-to-peak value of 1000 V or more is preferable.

  The cover 9 is a portion that is not in contact with the substrate A that is located on the opposite side of the rotating shaft 2c of the film forming roller 2 with respect to the portion 2a around which the substrate A is wound on the film forming roller 2 (that is, , The back side part) 2b is covered. As shown in FIG. 3, the cover 9 has a width that covers at least the arrangement region 2 e of the magnet 3 in the axial direction of each film-forming roller 2. For example, the cover 9 has the same width as the base material A.

  As shown in FIG. 2, the cover 9 has a shape that is bent in an arc shape along the portion 2 b on the back side of the film forming roller 2. Specifically, the cover 9 includes a metal main body portion 9a and an insulating portion 9b made of an insulating material. The main body 9a is made of a metal material such as stainless steel. The insulating portion 9b covers a portion of the main body portion 9a that faces the film forming roller 2.

The insulating material constituting the insulating portion 9b includes, for example, a ceramic material. Examples of the ceramic material include aluminum oxide (Al ₂ O ₃ ), zirconia (ZrO ₂ ), aluminum nitride (AlN), silicon carbide (SiC), and the like. In addition, a single material such as silicon oxide, polyimide, glass, or a laminate or a mixture thereof may be used. In the case of a plasma process containing oxygen, the insulating portion 9b is preferably an oxide.

Of these, aluminum oxide (Al ₂ O ₃ ) is particularly preferable among these ceramic materials because it has the best covering and insulating properties. Therefore, as the most preferable insulating portion 9b, one obtained by spraying alumina and / or an alumina-based compound on a portion of the main body portion 9a facing the film forming roller 2 is used.

  Further, the insulating material constituting the insulating portion 9b is more preferably a hard and strong material that is difficult to peel off even when polished. That is, when a film is formed on the surface of the insulating portion 9b of the cover 9 during the film forming operation, in order to remove the film, an operation of removing the film on the surface of the insulating portion 9b by polishing or the like is performed. Is called. During this polishing operation, if the insulating portion is made of an insulating material having a low hardness, there is a risk of being scraped and damaged. Therefore, it is preferable to use a hard and strong insulating material as described above. The material satisfying the performance required for the insulating portion 9b is preferably the ceramic material described above, and alumina and / or an alumina-based compound is particularly preferable among the ceramic materials.

  Moreover, it is preferable to coat the surface of the insulating part 9b with a fluororesin or the like so that the dirt attached to the surface of the insulating part 9b can be easily peeled off.

  As shown in FIG. 2, the clearance t1 between the cover 9 and the film forming roller 2 is preferably as narrow as possible in order to prevent the abnormal discharge in the film forming roller 2, for example, about 1 to 5 mm. Set to Further, the clearance t2 between the cover 9 and the substrate A is preferably as narrow as possible.

  In addition, the thickness d of the insulating portion 9b may be a thickness that can ensure an insulating property that does not cause abnormal discharge between the film forming roller 2 and peripheral members such as the inner wall of the chamber 1. For example, it may be 10 μm or more. Further, if the insulating portion 9b is thick, the effect of shielding the portion 2b on the back side of the film forming roller 2 is enhanced. As a result, the ability of the cover 9 to prevent occurrence of abnormal discharge and film formation in the back side portion 2b is improved. Further, the thickness C of the cover 9 is 0.5 mm or more in consideration of the rigidity of the cover 9 in order to maintain the clearance t1 between the cover 9 and the film forming roller 2. Is preferred.

  As shown in FIG. 4, the cover 9 is fixed to the side wall 1 a of the chamber 1 via a support structure 21. The support structure 21 includes a base portion 21 a fixed to the side wall of the chamber 1 and a connecting portion 21 b connected to the cover 9. The connecting portion 21b is connected to the outer peripheral surface of the cover 9 by welding or the like. The base portion 21a is fixed to the side wall 1a of the chamber 1 by screwing or the like.

  As the substrate A on which the film is formed, a thin strip-shaped member is employed. The thickness of the substrate A is preferably 5 μm or more. If the thickness is less than 5 μm, the base material A is easily deformed, for example, stretched, and it becomes difficult to stably wind the base material A around the surface of the film forming roller 2. On the other hand, when the thickness of the base material A is larger than 500 μm, the impedance becomes high and it becomes difficult to supply power to the plasma P from the film forming roller 2, and the transport of the base material A is not stable and abnormal discharge occurs. May occur. In consideration of these points, in the case where film formation is performed using the film forming apparatus 10 having the above-described configuration, if the base material A having a thickness of 5 to 500 μm is used, an abnormality may occur while using a thin base material. It is possible to carry out stably without generating discharge.

  Next, a method for forming a film on the surface of the substrate A using the film forming apparatus 10 configured as described above will be described.

  First, as shown in FIG. 1, the base material A before film formation is set at a predetermined location inside the vacuum chamber 1 in a state of a roll R <b> 1 wound in a roll shape. The strip-shaped substrate A drawn out from the roll R1 is wound around the right roller 2, the plurality of guide rollers 5, and the left film forming roller 2 in this order. The belt-like substrate A in this state is first transported through the low pressure chamber 7 by the rotation of the film forming roller 2 while being wound around the portion 2a of the right film forming roller 2, and further includes a plurality of guide rollers. In the state supported by 5, the inside of the high pressure chamber 8 is conveyed. The substrate A is conveyed inside the low pressure chamber 7 by the rotation of the film forming roller 2 while being wound around the portion 2a of the film forming roller 2 on the left side, and is positioned on the opposite side of the vacuum chamber 1 from the roll R1. In Fig. 2, the film is wound into a roll shape like the roll R2.

  At this time, the low-pressure chamber 7 of the vacuum chamber 1 is evacuated by a vacuum pump (not shown) through the exhaust port 15 and depressurized to a vacuum or a low-pressure state. In the low pressure chamber 7, the source gas G 1 is supplied from the source gas supply port 12, and the oxygen gas OX is supplied from the oxygen gas supply port 13. At the same time, oxygen gas OX is supplied into the high pressure chamber 8, and thereby the pressure in the high pressure chamber 8 is adjusted to be higher than the pressure in the low pressure chamber 7.

  At the same time, a high-frequency AC voltage is applied from the high-frequency power source 4 between the pair of film forming rollers 2 in the low-pressure chamber 7. A magnetic field is generated between the opposing portions 2 a of the pair of film forming rollers 2 by the magnet 3 in the vicinity of the portions 2 a. In the magnetic field region, the raw material gas G1 that receives power from the film forming roller 2 enters a plasma state, and plasma P is generated.

  As a result, the base material A conveyed from the roll R1 to the roll R2 forms a film when it contacts the plasma P inside the low pressure chamber 7 and between the pair of film forming rollers 2.

  On the other hand, the portion 2b on the back side of the film forming roller 2 around which the substrate A is not wound is covered with the cover 9, so that abnormal discharge is less likely to occur. Therefore, even if a part of the source gas G2 leaking from the low-pressure chamber 7 to the high-pressure chamber 8 through the opening 6a of the partition wall 6 reaches the back side portion 2b of the film forming roller 2, the source gas G2 remains in the back side portion 2b. The risk of forming a film by plasma formation is reduced.

  The film forming apparatus 1 described above has the following characteristics.

(1)
In the case of performing plasma CVD, in the state where an AC voltage for generating plasma P is applied to the film forming roller 2, the film forming roller is within a range where film forming is performed in the axial direction B of the film forming roller 2. Not only the portion 2a in which the two base materials A are wound and in contact with the base material A, but also the portion 2b on the back side not in contact with the base material A has a high potential so that the plasma P can be generated. It has become. In the film forming apparatus 10 of this embodiment, the cover 9 is located on the opposite side of the film forming roller 2 with respect to the portion 2a around which the substrate A is wound, with the rotation shaft 2c of the film forming roller 2 interposed therebetween. The back side portion 2 not in contact with the material A is covered. As a result, not only the portion 2a of the film forming roller 2 that is in contact with the substrate A but also the portion that is not in contact with the substrate A that is the portion 2b on the back side of the portion is covered with the cover 9. The occurrence of abnormal discharge in the back side portion 2b can be prevented.

  As a result, even when a high voltage is applied to the film forming roller 2 for the reason of increasing the power to improve the film quality such as the barrier property of the thin film formed during film formation, Abnormal discharge does not occur in the back portion 2b. Therefore, a film forming process with high power becomes possible, and film quality and productivity in the film forming operation can be improved.

(2)
In the film forming apparatus 10 of the present embodiment, the cover 9 includes an insulating material at least in a portion facing the film forming roller 2 (specifically, the insulating portion 9b). This insulating material insulates the film-forming roller 2 from its surroundings (for example, a grounded component such as the vacuum chamber 1 and a free roller (not shown)), so that the film-forming roller 2 and its surroundings are isolated. It is possible to prevent the occurrence of abnormal discharge in between. Thereby, it is possible to prevent the film formation on the film forming roller 2 and the surrounding objects.

  The cover 9 only needs to include an insulating material in at least a portion (insulating portion 9b) facing the film forming roller of the cover 9 as in the above embodiment, and the entire cover 9 may include the insulating material. Or the cover 9 may be comprised only from the insulating material.

(3)
In the film forming apparatus 10 of the present embodiment, as a more preferable aspect, the cover 9 is made of a metal main body portion 9a and the insulating portion that covers the portion of the main body portion 9a facing the film forming roller 2 made of the insulating material. 9b.

  In this configuration, the portion of the cover 9 that faces the film forming roller 2 in the metal main body 9a is covered with the insulating portion 9b made of an insulating material, so that the main body 9a is made of metal while the main body 9a is made of metal. It is possible to prevent the occurrence of abnormal discharge between the portion 9a and the film forming roller 2 and to prevent the formation of a film on the main body portion 9a. Further, the insulating portion 9b, which is generally a fragile material, can be reinforced by the main body portion 9a, and the possibility of breakage during mounting is reduced.

  In addition, since the cover 9 has the insulating portion 9b, any abnormal discharge of direct current and alternating current can be prevented.

(4)
In the film forming apparatus 10 of the present embodiment, the vacuum chamber 1 has a low-pressure, which is a film forming area in which the plasma P generated in the magnetic field region is present, and the base material A is formed using the plasma P. It has the chamber 7 and the high-pressure chamber 8 which is a non-film-forming area where the base material A is not formed. The film forming roller 2 has a portion 2 a disposed in the low pressure chamber 7 and a portion 2 b disposed in the high pressure chamber 8. The cover 9 is disposed in the high-pressure chamber 8 and covers the portion 2 b that is not in contact with the base material A in the film forming roller 2.

  In this configuration, the cover 9 covers the portion 2b that is not in contact with the base material A of the film forming roller 2 in the high-pressure chamber 8 that is a non-film forming area, thereby preventing the generation of a film on the portion 2b. Is possible.

(5)
The film forming apparatus 10 of this embodiment further includes a partition wall 6 that is disposed adjacent to the film forming roller 2 and divides the low pressure chamber 7 that is a film forming area and the high pressure chamber 8 that is a non-film forming area. . The pressure in the high pressure chamber 8 is set to be higher than the pressure in the low pressure chamber 7.

  In this configuration, the pressure in the high-pressure chamber 8 that is a non-film formation area is set to be higher than the pressure in the low-pressure chamber 7 that is a film formation area. When the gas to be fed is sent from the low pressure chamber 7 through the gap between the film forming roller 2 and the partition wall 6 (that is, the gap between the edge of the opening 6a of the partition wall 6 and the film forming roller 2 in FIG. 1). It is possible to suppress diffusion into the high pressure chamber 8. In addition, if the pressure in the high pressure chamber 8 is increased, discharge tends to occur in the portion 2 b of the film forming roller 2 disposed in the high pressure chamber 8, but the cover 9 is formed in the film forming roller in the high pressure chamber 8. Since the portion 2b that is not in contact with the two base materials A is covered, it is possible to prevent the occurrence of a film on the portion 2b.

(6)
In the film forming apparatus 10 according to the present embodiment, a ceramic material is used as an insulating material constituting the insulating portion 9b of the cover 9, so that the insulating property is better than other materials such as a resin material.

(7)
In the film forming apparatus 10 of the present embodiment, the insulating portion 9b is made of a material containing aluminum oxide, so that the covering property and the insulating property are the best as compared with other ceramic materials.

  The present invention is not limited to the embodiment described above. For example, the present invention includes the following modifications.

(A)
As shown in FIG. 5, the cover 9 covers the portion 2 b of the film forming roller 2 around which the base material A is not wound, over the entire length of the film forming roller 2 in the axial direction of the film forming roller 2. May be.

  It is preferable to omit the end cap 11 (see FIG. 3) that covers the end of the film forming roller 2 in order to avoid interference with the cover 9.

(B)
Moreover, the film forming apparatus according to the present invention may further include a roller insulating portion 22 as shown in FIGS. The roller insulating portion 22 is made of an insulating material and covers at least the range of the arrangement region 2 e of the magnet 3 (magnetic field generating portion) in the axial direction of the film forming roller 2 on the surface of the film forming roller 2. This roller insulation 22 allows the entire cover 9 to be made of a metal material.

  6 to 7, the roller insulating portion 22 covers at least the range of the magnet 3 placement region 2e in the axial direction of the film forming roller 2 on the surface of the film forming roller 2. As a result, the roller insulating portion 22 is located not only in the portion 2a around which the substrate A is wound in the film forming roller 2, but also on the opposite side of the portion 2a with the rotation axis of the film forming roller 2 interposed therebetween. The portion 2b not in contact with the substrate A is also covered. Therefore, even if the cover 9 is made of a metal material, the roller insulating portion 22 is interposed between the cover 9 and the film forming roller 2, thereby preventing the occurrence of abnormal discharge therebetween. 9 can be prevented from occurring. Thereby, as the cover 9, it is possible to use a metal component that is easy to process and maintain.

  Further, in the modification shown in FIGS. 6 to 7, the roller insulating portion 22 that covers the surface of the film forming roller 2, the portion 2 b on the back side of the portion in contact with the substrate A in the film forming roller 2, and its It is possible to prevent an abnormal DC discharge caused by a potential difference with a surrounding portion (for example, the inner wall of the vacuum chamber 1). At the same time, the cover 9 with a certain distance from the film forming roller 2 covers the back side portion 2b, so that a gap without plasma P is formed between the cover 9 and the film forming roller 2. As a result, it is possible to prevent alternating abnormal discharge caused by the plasma P. As a result, it is possible to prevent both AC and DC abnormal discharges in the portion 2b on the back side of the film forming roller 2.

  Further, since the roller insulating portion 22 covers the surface of the film forming roller 2, the insulating portion 9b (see FIG. 2) of the cover 9 can be omitted.

  Specifically, the roller insulating portion 22 covering the surface of the film forming roller 2 is, as shown in FIGS. 6 to 8, the axial direction B of the film forming roller 2 on the surface of the film forming roller 2. Covers the area where the magnet 3 is arranged and the surrounding area. In this modification, as shown in FIG. 8, the roller insulating portion 22 covers an area where the film forming roller 2 can come into contact with the base material A excluding the end portions 2 d on both sides. End portions 2 d on both sides of the film forming roller 2 are covered with end caps 11. The end cap 11 has a recess 11 a that fits into the end 2 d of the film forming roller 2. The surface of the end cap 11 is covered with an insulating portion 20 made of an insulating material.

  Specifically, the performance required for the roller insulating part 22 is a withstand voltage of 1000 V or more on the film forming roller 2 side and the plasma P side, and a material that is not damaged by the plasma P such as oxygen or organic Si. And so on. Here, if the withstand voltage of the roller insulating portion 22 is less than 1000 V, the roller insulating portion 22 cannot withstand the potential in the plasma P, and there is a risk of causing dielectric breakdown. In addition, a material that is easily damaged by the plasma P deteriorates during the plasma CVD, and therefore is not suitable as a material for the roller insulating portion 22.

Moreover, it is preferable that the insulating material which comprises the roller insulating part 22 contains a ceramic material similarly to the insulating part 9b of said cover 9. As shown in FIG. Examples of the ceramic material include aluminum oxide (Al ₂ O ₃ ), zirconia (ZrO ₂ ), aluminum nitride (AlN), silicon carbide (SiC), and the like. In addition, a single material such as silicon oxide, polyimide, glass, or a laminate or a mixture thereof may be used. In the case of a plasma process containing oxygen, the roller insulating portion 22 is preferably an oxide.

Of these, aluminum oxide (Al ₂ O ₃ ) is particularly preferable among these ceramic materials because it has the best covering and insulating properties. Therefore, as the most preferable insulating portion 9b, one obtained by spraying alumina and / or an alumina-based compound onto the film forming roller 2 is used.

  Further, the insulating material constituting the roller insulating portion 22 is more preferably a hard and strong material that is difficult to peel off even when polished, like the insulating portion 9b of the cover 9 described above. That is, a film formed by plasma CVD may be formed on the roller insulating portion 22 when the base material A meanders or at the back portion 2 b of the film forming roller 2. In order to remove this film, an operation of removing the film on the surface of the roller insulating portion 22 by polishing or the like is performed. During this polishing operation, if the insulating portion is made of an insulating material having a low hardness, there is a risk of being scraped and damaged. Therefore, it is preferable to use a hard and strong insulating material as described above. The material satisfying the performance required for the roller insulating portion 22 is preferably the above ceramic material, and among the ceramic materials, alumina and / or an alumina-based compound is particularly preferable.

  The insulating portion 20 on the surface of the end cap 11 may also be made of the same insulating material as the roller insulating portion 22 described above, but other insulating materials may be used.

  The thickness of the roller insulating portion 22 is set to be 1 to 500 μm as a thickness capable of reducing damage to the roller insulating portion 22 while stably generating the plasma P. That is, when the thickness of the roller insulating portion 22 exceeds 500 μm, the impedance becomes high and it becomes difficult to supply power to the plasma P from the film forming roller 2. On the other hand, if the thickness of the roller insulating portion 22 is less than 1 μm, the roller insulating portion 22 may break down due to the potential of the plasma P, or the roller insulating portion 22 may be physically damaged or peeled off due to contact with the substrate A or the like. May occur. Therefore, if the thickness of the roller insulating portion 22 is in the range of 1 to 500 μm as described above, power can be stably supplied to the plasma P and damage due to dielectric breakdown or the like of the roller insulating portion 22 can be reduced. It becomes possible to make it.

  Further, since the metal surface of the film forming roll 2 is covered with the roller insulating portion 22, even if the substrate A meanders in the axial direction B of the film forming roll 2, the film forming roll 2 is formed in the space where the plasma P is formed. The metal surface is not exposed. Therefore, abnormal discharge does not occur, and stable film formation and operation can be realized.

  Further, when a thin base A having a thickness of about 12 to 25 μm is used, since both the thin base A and the roller insulating portion 22 are interposed between the film forming roller 2 and the plasma P, the film is formed. It is possible to maintain high frequency impedance between the roller 2 and the plasma P. Therefore, the high frequency voltage can be set high. Thereby, the energy of ions and electrons in the vicinity of the substrate A is increased, and a good film can be formed even on the thin substrate A.

(C)
The present invention is not limited to a film forming apparatus provided with a pair of film forming rollers 2. For example, the present invention may be applied to a film forming apparatus including one film forming roller. In this case, the film forming apparatus may further include a counter electrode facing the film forming roller. The power source may apply a voltage for generating plasma to the film forming roller and the counter electrode.

1 Vacuum chamber 2 Film forming roller 3 Magnet (magnetic force generating means)
4 High-frequency power supply 9 Cover 10 Film forming apparatus 19 Insulating part

Claims (1)

A vacuum chamber;
A film-forming roller rotatably attached to the inside of the vacuum chamber, a metal film-forming roller in which a belt-like base material is wound around a part of the entire circumference of the film-forming roller;
A magnetic field generating unit that is disposed inside the film forming roller and generates a magnetic field outside a portion around which the base material is wound in the film forming roller;
A power source connected to the film forming roller and applying an alternating voltage to the film forming roller for generating plasma in the magnetic field region;
A cover that covers a non-contact portion that is not in contact with the base material that is located on the opposite side of the rotation axis of the film formation roller with respect to a portion around which the base material is wound in the film formation roller;
A film-forming area that is disposed adjacent to the film-forming roller and in which the plasma generated in the magnetic field region exists inside the vacuum chamber, and the base material is formed using the plasma And a partition partitioning into a non-film forming area where the base material is not formed,
The pressure in the non-film formation area is set to be higher than the pressure in the film formation area,
The film-forming roller has a portion arranged in the film-forming area and a portion arranged in the non-film-forming area,
It said cover includes a metallic main body, made of insulation material, and an insulating portion for covering a part facing the film-forming roller in the main body portion,
The cover is disposed only in the non-film formation area higher than the pressure in the film formation area so as to cover a non-contact portion that is not in contact with the base material in the film formation roller.
Plasma CVD film forming equipment.

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