JP2015196879A - plasma CVD film-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma CVD film-forming device that prevents the occurrence of an abnormal discharge where a substrate is not wound in a range in which a film is formed in an axial direction of a film-forming roller.SOLUTION: A plasma CVD film-forming device 10 includes: a vacuum chamber 1; a metal film-forming roller 2 which has a belt-like substrate wound around a part of the overall periphery of the film-forming roller 2; a magnetic field generation part 3 which is arranged in the film-forming roller 2, and generates a magnetic field outside the part of the film-forming roller 2, around which the substrate is wound; a power source 4 which is connected to the film-forming roller 2, and applies, to the film-forming roller 2, an AC voltage for generating plasma inside a region of the magnetic field; and an insulation part 9 which is made of an insulation material, and coverts a range of at least an arrangement region of the magnetic field generation part 3 in the axial direction of the film-forming roller 2, out of a surface of the film-forming roller 2.

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, a plasma CVD film forming apparatus includes a vacuum chamber filled with a raw material gas that is a raw material for a film, and a sheet-like substrate that is disposed in the vacuum chamber and is a film formation target. A pair of film-forming rollers around which the material is wound, a power source in which electrodes are connected to the pair of film-forming rollers, and magnetic field generating means provided inside the pair of film-forming rollers, respectively.

  The film forming roller is a cylinder made of metal such as stainless steel. Insulating shielding members are provided at both ends of the film forming roller. The shielding member is provided at both ends of the film forming roller and mainly at a portion where the base material is not wound.

  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 while being wound around 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.

  Further, the film forming apparatus includes a shielding member that covers both ends of the film forming roller and the portion around which the base material is not wound. This shielding member prevents an abnormal discharge from occurring in the unwrapped portion.

JP 2011-149059 A

  In the film forming apparatus described above, both end portions of the film forming roller and portions where the base material is not wound are covered with the shielding member. However, in the range where the film is formed in the axial direction of the film forming roller, a base material is wound around a part of the peripheral surface of the film forming roller, and the surface of the metal film forming roller is Although it is covered with the base material, the other part, that is, the part where the base material is not wound is exposed to the outside because it is 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 present inventor considered that the entire peripheral surface of the metal film-forming roller is within the range where film formation is performed in the axial direction of the film-forming roller under the condition that a high voltage is applied to the film-forming roller in order to perform plasma CVD. Even if covered with an insulating part, it is possible to generate a plasma on the outside of the film forming roller and form a film on the surface of the substrate wound around the film forming roller. It has been found that it is possible to insulate a portion where the substrate is not wound. Based on this finding, the present inventor has created the following invention.

  That is, in order to solve the above problems, a plasma CVD film-forming apparatus of the present invention includes a vacuum chamber and a film-forming roller that is rotatably attached to the inside of the vacuum chamber. A metal film-forming roller that is wound around a part of the entire circumference of the film-forming roller, and a magnetic field that is disposed inside the film-forming roller and outside the portion of the film-forming roller on which the substrate is wound A magnetic field generation unit that generates a plasma, a power source that applies an AC voltage for generating plasma in the magnetic field region to the film formation roller, an insulating material, and the film formation roller. And an insulating part that covers at least the range of the arrangement area of the magnetic field generation part in the axial direction of the film forming roller.

  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 portion that is wound and is in contact with the substrate, but also the portion on the back side that is not in contact with the substrate is at a potential at which plasma can be generated. For this reason, abnormal discharge is likely to occur in the portion on the back side that is not in contact with the base material. Therefore, in the present invention, the insulating portion made of an insulating material covers at least the range of the arrangement region of the magnetic field generating portion in the axial direction of the film forming roller on the surface of the film forming roller. As a result, not only the part of the film forming roller that is in contact with the base material but also the part that is not in contact with the base material that is the back side of the part is covered with the insulator, and the back side part. It is possible to prevent the occurrence of abnormal discharge.

  Moreover, it is preferable that the said insulation part covers the whole surface of the said film-forming roller.

  According to such a configuration, since the entire surface of the metal film forming roller is covered with the insulating portion, all the portions of the film forming roller that are exposed to the outside are eliminated, so that the occurrence of abnormal discharge can be more reliably prevented. Is possible.

  The insulating part preferably has a thickness of 1 to 500 μm.

  The present inventor has earnestly studied the thickness of the insulating portion that can reduce damage to the insulating portion while stably generating plasma under the condition that a high voltage is applied to the film forming roller for performing plasma CVD. Research has been done to find the optimum thickness range for the insulation as described above. That is, since the thickness of the insulating portion is 1 μm to 500 μm as described above, it is possible to reliably supply power to the plasma from the film forming roller. At the same time, it is possible to reduce the possibility that the insulating portion breaks down due to the plasma potential, or that the insulating portion physically breaks or peels off due to contact with the base material.

  The fixing mask further includes a fixed mask disposed outside the film forming roller and detachably attached to the vacuum chamber. The fixed mask has an opening having a width that defines the plasma generation region. preferable.

  According to this configuration, when film formation is performed on substrates having various widths, only the fixed mask disposed outside the film formation roller is maintained while maintaining the state where the film formation roller is attached to the vacuum chamber. Is exchanged, it is possible to cope with the width of film formation on each substrate. In other words, since the fixed mask has an opening with a width that defines the plasma generation region, it is possible to adjust the plasma generation width without replacing the film forming roller by simply replacing the fixed mask. As a result, it is possible to easily change the width of film formation.

  Moreover, it is preferable that the said opening is arrange | positioned inside the arrangement | positioning area | region of the said magnetic field production | generation part in the axial direction of the said film-forming roller.

  According to this configuration, it is possible to limit the plasma generation region within the range of the arrangement region of the magnetic field generation unit by the width of the opening of the fixed mask. Thereby, the base material is formed into a film using the plasma generated within the range of the opening of the fixed mask. On the other hand, since no plasma is generated outside the range of the opening of the fixed mask, a portion of the substrate located outside the range is not formed. As a result, it is possible to accurately limit the film formation region on the substrate. Moreover, even if the plasma generated inside the opening of the fixed mask enters the gap between the fixed mask and the film forming roller, at least the surface of the film forming roller that is in contact with the substrate is covered with an insulating part. Abnormal discharge does not occur.

  Moreover, it is preferable to further include a cover that covers a portion of the film forming roller that is in contact with the base material and a portion on the back side that is not in contact with the base material.

  According to such a configuration, the insulating portion that covers the surface of the film forming roller causes the portion on the film forming roller that is in contact with the substrate to the portion on the back side that is not in contact with the substrate and the surrounding portion ( For example, an abnormal direct current discharge caused by a potential difference with the inner wall of the vacuum chamber) is prevented. At the same time, a cover with a certain distance from the film forming roller covers the above-mentioned back side portion, so that a plasma-free gap is formed between the cover and the film forming roller. It is also possible to prevent abnormal discharge. As a result, it is possible to prevent both alternating current and direct current abnormal discharge in the back side of the film forming roller.

  Further, it is preferable that the insulating material includes a ceramic material having good insulating properties. The ceramic material preferably contains an oxide of aluminum having the best covering and insulating properties.

  As described above, according to the plasma CVD film forming apparatus of the present invention, it is possible to prevent the occurrence of abnormal discharge in the portion on the back side with respect to the portion in contact with the base material in the film forming roller.

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 plan view around a pair of film forming rollers of the plasma CVD film forming apparatus of FIG. 1. FIG. 3 is an exploded plan view in a state where an end cap is removed from an end of the film forming roller of FIG. 2. It is an enlarged plan view around a pair of film forming rollers showing the structure of a plasma CVD film forming apparatus provided with a fixed mask according to a modification of the present invention. 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 of FIG. FIG. 5 is an enlarged view showing a fixed mask mounting structure at one end of the film forming roller of FIG. 4.

  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 and 2 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 includes a high-frequency power source 4 that applies a high-frequency AC voltage, a plurality of guide rollers 5, and a partition wall 6 that partitions the inside of the vacuum chamber 1. Further, the film forming apparatus 10 includes an insulating portion 9 that covers the surface of each film forming roller 2.

  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 a partition wall 6. 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.

  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, a discharge is generated between the pair of film forming rollers 2, and the source gas G <b> 1 is in a plasma state in the magnetic field region near the magnet 3 to generate 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 insulating portion 9 that covers the surface of each film forming roller 2 is made of an insulating material, and the magnet 3 is disposed in the axial direction B of the film forming roller 2 on the surface of the film forming roller 2 (see FIGS. 2 to 3). And the surrounding area. In the present embodiment, as shown in FIG. 3, the insulating portion 9 covers a region of the film forming roller 2 that can contact 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 19 made of an insulating material.

The insulating material constituting the insulating part 9 includes 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 9 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 9, one obtained by spraying alumina and / or an alumina-based compound onto the film forming roller 2 is used.

  Specifically, the performance required for the insulating part 9 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. There are things. Here, if the withstand voltage of the insulating part 9 is 1000 V or less, the insulating part 9 cannot withstand the potential in the plasma P, and there is a risk of causing dielectric breakdown. Further, 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 insulating portion 9.

  The insulating material constituting the insulating portion 9 is more preferably a hard and strong material that does not easily peel off even when polished. That is, a film formed by plasma CVD may be formed on the insulating portion 9 when the base material A meanders or at a portion 2 b on the back side of the film forming roller 2. In order to remove the film, an operation of removing the film on the surface of the insulating portion 9 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 insulating portion 9 is preferably the above ceramic material, 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 9 with a fluororesin or the like so that the dirt attached to the surface of the insulating part 9 can be easily peeled off.

  The insulating portion 19 on the surface of the end cap 11 may be made of the same insulating material as the insulating portion 9 described above, but other insulating materials may be used.

  The thickness of the insulating portion 9 is set to be 1 to 500 μm as a thickness capable of reducing damage to the insulating portion 9 while stably generating the plasma P. That is, when the thickness of the insulating portion 9 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 insulating portion 9 is less than 1 μm, the insulating portion 9 may break down due to the potential of the plasma P, or the insulating portion 9 may be physically damaged or peeled off due to contact with the base material A or the like. and so on. Therefore, if the thickness of the insulating portion 9 is in the range of 1 to 500 μm as described above, it is possible to stably supply power to the plasma P and to reduce damage due to dielectric breakdown of the insulating portion 9 or the like. Is possible.

  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, such as stretched, and it becomes difficult to stably wind the base material A around the surface of the film forming roller 2 covered with the insulating portion 9. 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, when film formation is performed using the film formation apparatus 1 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 1 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. 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 through the insulating portion 9 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 base material A is not wound is covered with the insulating portion 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.

(Feature)
(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 1 of the present embodiment, the insulating portion 9 made of an insulating material covers at least the range of the arrangement region of the magnet 3 in the axial direction B of the film forming roller 2 on the surface of the film forming roller 2. . Thereby, not only the part 2a which the base material A in the film-forming roller 2 is contacting but the part which is not contacting the base material A which is the part 2b of the back side with respect to the part is covered with the insulation part 9. Thus, it is possible to prevent the occurrence of abnormal discharge in the back side portion 2b.

  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.

  Further, since the metal surface of the film forming roll 2 is covered with the insulating portion 9, even if the substrate A meanders in the axial direction B of the film forming roll 2, the film forming roll 2 has a space in which 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 insulating portion 9 are interposed between the film forming roller 2 and the plasma P, the film forming roller It is possible to keep the high frequency impedance between 2 and the plasma P high. 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.

(2)
In the film forming apparatus 1 of this embodiment, since the thickness of the insulating portion 9 is 1 to 500 μm, it is possible to reduce damage to the insulating portion 9 while stably generating the plasma P. That is, since the thickness of the insulating portion 9 is 1 μm or more, the insulating portion 9 may break down due to the potential of the plasma P, or the insulating portion 9 may be physically damaged or peeled off due to contact with the base material A or the like. Etc. can be reduced. In addition, since the insulating portion 9 has a thickness of 500 μm or less, it is possible to reliably supply power to the plasma P from the film forming roller 2.

(3)
In the film forming apparatus 1 according to the present embodiment, since a ceramic material is used as an insulating material constituting the insulating portion 9, the insulating property is better than other materials such as a resin material.

(4)
In the film forming apparatus 1 of this embodiment, the insulating part 9 is made of a material containing an oxide of aluminum, so that the covering property and the insulating property are the best as compared with other ceramic materials.

(Modification)
(A)
In the above embodiment, the plasma P is formed over the entire arrangement region of the magnet 3 in the axial direction B of the film forming roll 2, but the present invention is not limited to this, and is shown in FIGS. As described above, a mask 21 for defining the generation region of the plasma P may be provided.

  That is, as a modification of the present invention, the film forming apparatus shown in FIGS. 4 to 6 further includes a mask 21 in addition to the structure of the film forming apparatus 10 shown in FIGS.

  The mask 21 is disposed outside the film forming roller 2 and is detachably attached to the vacuum chamber 1. The mask 21 has an opening 23 having a width that defines a region where the plasma P is generated.

  Specifically, the mask 21 has a first portion 21 a and a second portion 21 b that are separated from each other by the width W1 of the opening 23 in the axial direction B of the film forming roller 2. These first portions 21 a and 21 b are each made of a plate material that is curved in an arc shape so as to extend along the outer peripheral surface of the film forming roller 2.

  The mask 21 may be made of a metal material or an insulating material. Alternatively, as the fixed mask 21, a metal plate whose surface is covered with an insulating material may be used. In particular, a metal material is preferable as the material of the mask 21 in that it is difficult to be damaged by mechanical deformation when the film attached to the mask 21 is removed.

Further, it is more preferable that an insulating material layer is formed on the surface of the metal material in advance so that the electrical characteristics are not easily changed when the film adheres to the surface of the metal material. As a metal material used as the material of the mask 21, iron, stainless steel, aluminum, copper, or alloys thereof are preferable. As the insulating material, SiO _x (silica), Al ₂ O ₃ (alumina), a fluorine compound, or a mixture thereof is preferable. Further, in terms of strength, a material sprayed with an insulating material is preferable, but a material coated with an insulating material may be used.

  Furthermore, the potential of the mask 21 may be matched with the potential of the vacuum chamber 1 or may be a floating potential. In particular, the potential of the mask 21 is preferably matched to the potential of the vacuum chamber 1 in that the potential around the mask 21 is stable and abnormal discharge is unlikely to occur.

  The first portion 21 a and the second portion 21 b of the mask 21 are arranged at positions where a gap 30 is formed from the outer peripheral surface of the film forming roller 2. The first portion 21 a and the second portion 21 b are each fixed to the inner wall of the vacuum chamber 1 via a pedestal 22. The pedestal 22 has a pedestal portion 22a fixed to the inner wall of the bottom or side of the vacuum chamber 1, and a pair of arm portions 22b extending upward from the pedestal portion 22a. The first portion 21a and the second portion 21b are fixed to the tip of each arm portion 22b by welding or the like.

  The pedestal 22 is detachably attached to the vacuum chamber 1 so as to facilitate maintenance such as removal of dirt adhered during film formation. The pedestal 22 is preferably made of a metal material such as stainless steel or aluminum so that the attached dirt can be easily removed. Further, the surface of the metal material may be covered with an insulating material. Furthermore, the pedestal 22 is preferably arranged at a position lower than the path through which the substrate A passes so that dirt attached to the pedestal 22 falls and does not adhere to the substrate A.

  An opening 23 having a width W1 is formed between the first portions 21a and 21b of the mask 21 arranged as described above.

  The opening 23 is arranged inside the arrangement region L1 of the magnet 3 in the axial direction B of the film forming roller 2.

  The distance between the mask 21 and the film forming roll 2 is preferably narrow in terms of preventing plasma from entering these gaps 30 (see FIG. 4). Therefore, this interval is as narrow as possible so that the base material A wound around the surface of the film forming roll 2 (specifically, the surface of the insulating portion 9 covering the film forming roll 2) and the mask 21 do not contact each other. Is set to be

  As described above, in the film forming apparatus of the modification shown in FIGS. 4 to 6, when film forming is performed on the substrate A having various widths, the film forming roller 2 is attached to the vacuum chamber 1. It is possible to cope with the width of film formation on each substrate A by exchanging only the mask 21 disposed outside the film forming roller 2 while maintaining the film. That is, since the mask 21 has the opening 23 having a width that defines the generation region of the plasma P, the width of the generation of the plasma P can be adjusted by simply replacing the mask 21 without replacing the film forming roller 2. As a result, it is possible to easily change the width of film formation.

  Therefore, when the base material A having a narrow width is formed, for example, when the width W3 of the base material A is narrower than the length L1 of the arrangement region of the magnet 3 as shown in FIG. By installing the mask 21 having the opening 23 narrower than the width W3 on the outside of each film forming roller 2, the generation region of the plasma P can be limited to the inside of the opening 23. Thereby, even if it is the narrow base material A, it is possible to perform the stable film-forming process within the width W 1 of the predetermined opening 23.

  Even if the plasma P inside the opening 23 of the mask 21 enters the gap 30 between the mask 21 and the film forming roller 2, the surface of the film forming roller 2 is covered with the insulating portion 9, so that abnormal discharge occurs. There is no fear.

  Here, when film formation is performed by plasma CVD as in the above-described film formation apparatus, the film formation roller is different from other film formation methods such as vapor deposition and sputtering in which the potential of the film formation roller is low potential such as the chamber potential. Thus, high frequency power is applied to the film forming roller 2. Therefore, insulation of the film forming roller 2 is important.

  Therefore, in a conventional plasma CVD film forming apparatus having a roller with an exposed metal surface, when changing the width of the base A, the base is to prevent abnormal discharge near the end of the base A. It is necessary to replace the film forming roller unit with a magnet that fits the width of the material A. Further, replacement of the film forming roller requires a lot of cost and time. Conventionally, when the width of the base material is changed, an insulating tape may be wound around the surface of the film forming roller near the end portion of the base material A to insulate the vicinity of the end portion. However, in this case, the insulating tape affixed to the surface of the film forming roller gives a step-like deformation to the base material A, or creates a minute gap between the base material A and the film forming roller. There is a problem that current flow is disturbed and stable plasma cannot be formed.

  On the other hand, since the film forming apparatus according to the modification of the present invention shown in FIGS. 4 to 6 includes the film forming roller 2 and the mask 21 covered with the insulating portion 9, the film forming roller 2 is provided. In response to changing the width of the base material, the mask 21 having an opening width corresponding to the width of the base material is replaced or the position of the mask 21 is adjusted to change the opening width. By adjusting, film formation can be performed stably without causing abnormal discharge through the gap between the mask 21 and the film formation roller 2.

  4 to 6, the opening 23 is arranged inside the arrangement region L1 of the magnet 3 in the axial direction B of the film forming roller 2. Therefore, it is possible to limit the generation region of the plasma P within the range L1 of the arrangement region of the magnet 3 by the width W1 of the opening 23 of the mask 21. Thereby, the base material A is formed in the range of the opening 23 of the mask 21 by using the plasma P generated within the range. On the other hand, since the plasma P is not generated outside the range of the opening 23 of the mask 21, the portion of the base material A located outside the range is not formed. As a result, it is possible to accurately limit the film formation region on the substrate A.

  That is, as shown in FIG. 6, the magnet 3 in the film forming roller 2 forms an elongated plasma P in the axial direction of the film forming roller 2 on the substrate A wound around the film forming roller 2. A strong film is formed at the location where the elongated plasma P is formed.

  In the film forming apparatus shown in FIGS. 4 to 6, a mask 21 having an opening 23 having a width W1 narrower than the length L1 of the magnet 3 inside the film forming roller 2 is arranged so as to cut off the elongated plasma P. Yes. As a result, only the central region of the elongated plasma P is left, and the film formation region is limited. Since the elongated plasma P is not formed in the portion covered with the mask 21, no film is formed, and an unnecessary film is formed on the end of the base A or the end of the film forming roller 2 where the base A is not wound. Can be prevented.

  The mask 21 has a function of cutting off the elongated plasma P. It is necessary to narrow the gap between the insulating portion 9 and the mask 21 disposed on the film forming roller 2 so that the plasma P does not grow inside the gap. Under the condition of a process pressure of several Pa, the gap between the insulating portion 9 and the mask 21 is preferably set to 5 mm or less. In the process conditions where the pressure is low, the interval can be widened, but the interval is preferably 10 mm or less in order to avoid the deposition of diffused film-forming particles.

  Note that the end of the elongated plasma P is cut off by the mask 21, and the circulation of the plasma P is disturbed at the end. Therefore, a magnetic field that assists the stability of the plasma P may be applied by installing an auxiliary magnet in the film forming roller 2, the mask 21, or around the mask 21.

  In the film forming apparatus having the mask 21 shown in FIGS. 4 to 6, the mask 21 does not need to cover both ends of the film forming roller 2, and at least both ends in the width direction of the substrate A to be formed. If the film is disposed at a position that protects the film, film formation on the surface of the film forming roller 2 that is out of the predetermined film forming range, for example, both ends of the base A or in the vicinity of the end of the base A is prevented. It is possible.

  The overlapping width W2 between the base material A and the mask 21 is preferably narrow in that the film-forming area on the base material A can be expanded, while the stain due to the adhesion of the film on both ends of the base material A can be suppressed. The wider one is preferable. Considering these points, the width W2 is preferably set to about several millimeters to several centimeters.

  Further, the portion of the film forming roller 2 that does not overlap the base material A may be covered with the end cap 11 whose surface is covered with the insulating portion 19 as in the above embodiment, or covered with the insulating portion 9. Also good.

  Furthermore, the distance t1 between the mask 21 and the end cap 11 is preferably narrow (for example, about several millimeters) in terms of preventing plasma from entering through these gaps. However, when the distance from the plasma P inside the opening 23 is sufficiently long and the plasma does not reach the gap, the interval t1 may be wide.

  Here, if the width of the end cap 11 is increased without using the mask 21, it is possible to cope with the width of the substrate A while preventing abnormal discharge at the end of the film forming roller 2. However, as described above, if both the mask 21 and the end cap 11 are used, the gap between the base material A and the end cap 11 at the end of the film forming roller 2 can be covered with the mask 21. It is possible to prevent film formation on the film forming roller 2 in the gap.

(B)
Further, as another modification of the present invention, a cover 31 (see FIG. 5) that covers a portion 2 b of the film forming roller 2 that is not in contact with the substrate A with respect to a portion 2 a that is in contact with the substrate A. ) May be further provided. In this configuration, first, the insulating portion 9 that covers the surface of the film forming roller 2 is used to form a portion 2b on the back side of the portion of the film forming roller 2 that is in contact with the substrate A and the surrounding portion (for example, the vacuum chamber 1). DC abnormal discharge due to potential difference with the inner wall of the At the same time, the cover 31 with a certain distance from the film forming roller 2 covers the above-described back portion 2b, so that a gap without plasma P is formed between the cover 31 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.

(C)
In the above-described embodiment, the insulating portion 9 covers a region of the film forming roller 2 that contacts the base material A except for the end portions 2d on both sides, and the end portions 2d on both sides are end caps covered with the insulating portion 19. However, the present invention is not limited to this. As a modification of the present invention, the insulating portion 9 may cover the entire surface of the film forming roller 2. In this case, since the entire surface of the metal film forming roller 2 is covered with the insulating portion 9, there is no portion exposed to the outside in the film forming roller 2, so that the occurrence of abnormal discharge can be prevented more reliably. Is possible.

(D)
In the above embodiment, a film forming apparatus including a pair of film forming rollers 2 is shown. However, the present invention is not limited to this, and is applied to a film forming apparatus including one film forming roller. May be. 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 Insulating part 10 Film forming apparatus 21 Mask 23 Opening part

Claims (8)

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;
An insulating part that is made of an insulating material and covers at least the range of the arrangement region of the magnetic field generation unit in the axial direction of the film forming roller of the surface of the film forming roller
Plasma CVD film forming equipment. The insulating portion covers the entire surface of the film forming roller.
The plasma CVD film-forming apparatus according to claim 1. The insulating part has a thickness of 1 to 500 μm.
The plasma CVD film-forming apparatus according to claim 1 or 2. Further comprising a mask disposed outside the film forming roller and detachably attached to the vacuum chamber;
The mask has an opening having a width that defines the plasma generation region.
The plasma CVD film-forming apparatus of any one of Claims 1-3. The opening is arranged inside the arrangement region of the magnetic field generation unit in the axial direction of the film forming roller.
The plasma CVD film-forming apparatus according to claim 4. A cover that covers a portion of the film forming roller that is in contact with the substrate and a portion on the back side that is not in contact with the substrate;
The plasma CVD film-forming apparatus of any one of Claims 1-5. The insulating material includes a ceramic material,
The plasma CVD film-forming apparatus of any one of Claims 1-6. The ceramic material includes an oxide of aluminum,
The plasma CVD film-forming apparatus according to claim 7.

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