JP5206411B2 - Thin film forming apparatus and thin film forming method - Google Patents

Description

  The present invention relates to a thin film forming apparatus and a thin film forming method.

  In recent years, various products such as LSIs, semiconductors, display devices, magnetic recording devices, photoelectric conversion devices, etc. have many materials in which high-functional thin films such as electrode films, dielectric protective films, and semiconductor films are provided on a substrate. It is used.

  Conventionally, such a high-functional thin film is formed by a wet film formation method represented by a coating method, or a dry film formation method using a vacuum such as a sputtering method, a vacuum evaporation method, or an ion plating method. Has been.

  However, recently, for example, the atmospheric pressure plasma discharge processing thin film forming method can provide a higher performance thin film than the above-mentioned wet film forming method, and the productivity is higher than the dry film forming method using vacuum. Therefore, it has been devised and put into practical use (for example, see Patent Document 1). The greatest merit of the atmospheric pressure plasma discharge processing method is that it is not necessary to make a vacuum, so that continuous film formation is possible as in the coating method.

  And especially regarding the thin film formation method by atmospheric pressure plasma discharge, many things regarding the processing apparatus regarding forming a film continuously and forming a thin film uniformly are seen in patent documents.

  For example, Patent Document 2 includes a pair of counter electrodes having a first electrode and a second electrode, and a discharge portion formed between the counter electrodes, and a side close to one of the counter electrodes in the discharge portion The base material processed while passing through is conveyed to the discharge part while passing again through the side near the other electrode of the counter electrode by the folding transfer means. Means for supplying a reaction gas at atmospheric pressure or a pressure in the vicinity thereof between substrates that reciprocate and pass in the discharge part, and applying different high-frequency voltage components to the first electrode and the second electrode, respectively The description relates to a plasma discharge treatment apparatus.

  Further, there can be found literature relating to means for homogenizing a thin film by controlling the flow of reaction gas.

  For example, in patent document 3, it has the structure which is equipped with the opposing roll electrode which consists of a roll electrode which one side rotated and the other fixed, and the base material which forms a film | membrane passes between roll electrodes. It is described that the flow path through which the reaction gas flows serves as a guide mechanism for the gas flow path by making the upstream portion and the downstream portion of the gap between the opposed roll electrodes symmetrical.

In Patent Document 4, as in Patent Documents 2 and 3, an apparatus for supplying a mixed gas between discharge plasma processing electrodes in which electrodes provided opposite to each other with a constant discharge space in a roll shape are supplied to perform discharge plasma processing. It is. In addition, a gas leakage prevention skirt is described in which the reaction gas introduction port and the suction port are covered as close as possible to the electrode surface until the vicinity of the position where the substrate and the roll electrode are in contact with each other.
JP-A-2-48626 JP 2004-189958 A JP 2003-93870 A JP 2001-279457 A

  However, in any of the above-mentioned patent documents, a part of the gas containing the raw material supplied from the processing gas discharge means to the film forming space does not contribute to the film forming, but as fine particles (particles) in the film forming space. There is no mention of problems caused by floating. That is, this particle gradually progresses with the treatment time, and accumulates on the electrode surface and the surface of the substrate to be treated, and further mixed into the film formation of the substrate, whereby the film quality (haze) of the thin film deteriorates and the particles The state of discharge changes as a result of scattering in the reaction vessel including the electrode surface. As a result, continuous and stable treatment and film formation become difficult.

  The present invention has been made in view of the above problems, and its purpose is to adjust the flow resistance of gas and the flow rate of supply and exhaust in a thin film formation method by atmospheric pressure plasma discharge, and suspended fine particles It is providing the thin film formation apparatus and thin film formation method which are not mixed in the film formation of this.

The above object of the present invention has been achieved by the following constitution.
1. A thin film forming apparatus for forming a thin film by performing plasma discharge treatment on the surface of a substrate to be continuously transferred under atmospheric pressure or a pressure in the vicinity thereof,
A pair of roll electrodes facing and rotating with a predetermined gap;
Plasma discharge means for generating a plasma discharge by applying a voltage to the pair of roll electrodes;
Transfer means for transferring the substrate to the plasma discharge means;
A processing gas discharge means for discharging a processing gas in the direction of the predetermined gap to the base material passing through the plasma discharge means;
Gas discharge means for discharging the gas after the processing gas has passed through the plasma discharge means;
Between the processing gas discharge means and the surface of the pair of roll electrodes, a coating space portion having a certain space in the axial direction along the surface of the roll electrode;
Have
The process gas comprises a flow resistance Pa experienced when passing in front Symbol covering space, said pair of rolls electrodes, and the flow resistance Pb experienced when passing through the predetermined gap, the ratio of,
1 <Pa / Pb
And
And the ratio of the gas exhaust flow rate Qout of the exhaust gas taken in by the gas discharge means and the gas discharge flow rate Qin of the gas from which the processing gas discharge means discharges the processing gas is:
1 <Qout / Qin
A thin film forming apparatus characterized by the above.
2. The process gas comprises a Re before Symbol flow resistance Pa, said the flow resistance Pb, the ratio of,
10 ≦ Pa / Pb ≦ 1000
2. The thin film forming apparatus according to 1, wherein
3. And the gas exhaust flow rate Qout, is the ratio between the front Kiga scan discharge flow rate Qin,
2 ≦ Qout / Qin ≦ 10
2. The thin film forming apparatus according to 1, wherein
4). Before Symbol pair of rolls electrodes, the distance b of the predetermined gap,
0.1 ≦ b ≦ 2.0 (mm)
Or
The arc viewed from the axial direction of the covering space portion has an angle θ from the center of the roll electrode,
π / 18 ≦ θ
Being
2. The thin film forming apparatus according to 1, wherein at least one of the following holds:
5. Surface facing the coating space portion of the process gas discharging means has a rough surface that is concave convex, the distance Hb1 from the surface RH of the roll electrode to the convex portion, the distance Hb2 from the surface RH until recess The ratio of Hb1 / Hb2 ≦ 0.5
2. The thin film forming apparatus according to 1, wherein
6). A mechanism for applying heat to pre-Symbol the covering space, and the temperature Ta of the process gas when the process gas passes through the coating space, the pair of rolls electrodes passes through the predetermined gap to be discharged The ratio of the processing gas temperature Tb to 1 ≦ Ta / Tb
2. The thin film forming apparatus according to 1, wherein
7). A thin film forming method for forming a thin film by performing plasma discharge treatment under atmospheric pressure or a pressure in the vicinity thereof on the surface of a substrate to be continuously transferred,
A pair of roll electrodes facing and rotating with a predetermined gap;
A plasma discharge step of generating a plasma discharge by applying a voltage to the pair of roll electrodes;
A transfer step of transferring the substrate to the plasma discharge step;
A processing gas discharge step of discharging a processing gas in the direction of the predetermined gap to the base material passing through the plasma discharge step;
A gas discharge step of discharging the gas after the processing gas has passed through the plasma discharge step;
Between the process gas discharge step and the surfaces of the pair of roll electrodes, a covering space portion having a constant space in the axial direction along the surface of the roll electrodes;
Have
The ratio between the flow resistance Pa received when the processing gas passes through the coating space and the flow resistance Pb received when the processing gas passes through the predetermined gap between the pair of roll electrodes is:
1 <Pa / Pb
And
And the ratio of the gas exhaust flow rate Qout of the exhaust gas taken in by the gas discharge step and the gas discharge flow rate Qin of the gas from which the processing gas discharge step discharges the processing gas is:
1 <Qout / Qin
A method for forming a thin film, characterized in that
8). The process gas has a ratio of the flow resistance Pa to the flow resistance Pb.
10 ≦ Pa / Pb ≦ 1000
8. The thin film forming method according to 7, wherein
9. The ratio of the gas exhaust flow rate Qout and the gas discharge flow rate Qin is:
2 ≦ Qout / Qin ≦ 10
8. The thin film forming method according to 7, wherein
10. The distance b between the predetermined gaps of the pair of roll electrodes is
0.1 ≦ b ≦ 2.0 (mm)
Or
The arc viewed from the axial direction of the covering space portion has an angle θ from the center of the roll electrode,
π / 18 ≦ θ
Being
8. The thin film forming method according to 7, wherein at least one of the above holds.
11. The surface facing the coating space portion of the process gas discharge step has a rough surface that is uneven, a distance Hb1 from the surface RH to the convex portion of the roll electrode, and a distance Hb2 from the surface RH to the concave portion, The ratio of Hb1 / Hb2 ≦ 0.5
8. The method for forming a thin film according to 7, wherein
12 A mechanism for applying heat to the coating space, and a temperature Ta of the processing gas when the processing gas passes through the coating space, and a time when the pair of roll electrodes pass through the predetermined gap The ratio of the processing gas temperature Tb is 1 ≦ Ta / Tb
8. The thin film forming method according to 7, wherein

  According to the present invention, the flow resistance value received when the processing gas passes through the coating space between the processing gas discharge means and the surfaces of the pair of roll electrodes receives the flow received when passing through the gap between the pair of roll electrodes. If the gas exhaust flow rate at the exhaust gas discharge means is larger than the resistance value and larger than the gas supply flow rate at the process gas discharge means, fine particles (particles) are not mixed in the film formation and the film quality (haze) of the thin film is reduced. Deterioration can be suppressed.

It is a figure which shows the plasma discharge processing apparatus used for the manufacturing method of this invention. It is a figure which shows a process gas discharge means. It is the figure which showed the covering space part typically. The figure showing the unevenness | corrugation of the surface which faces the coating | coated space part of the process gas discharge part as the distance Hb1 from the surface RH of a roll electrode to a convex part, and the distance Hb2 from the surface RH to a recessed part.

Explanation of symbols

10A, 10B Roll electrode 11A, 11B, 11C, 11D U turn roll 20 Guide roll 30 Process gas discharge means 40 Gas discharge means 100 Discharge gap (discharge part)
302A, 302B Covering space 80 Power supply F Base material G Processing gas

  An embodiment of the present invention will be described. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not restricted to this embodiment. In addition, the following assertive description in the embodiment of the present invention shows the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

[Plasma discharge treatment equipment]
FIG. 1 is an example of a plasma discharge processing apparatus used in the manufacturing method of the present invention, and is a diagram schematically showing a plasma discharge processing apparatus that performs processing by reciprocating a substrate using two roll electrodes. This apparatus has a pair of roll electrodes 10A (first electrode) and a roll electrode 10B (second electrode). A power supply 80 capable of applying a voltage for plasma discharge is connected to these roll electrodes 10A and 10B via voltage supply means 81 and 82.

  The roll electrodes 10 </ b> A and 10 </ b> B are rotating electrodes that can be rotated while winding the base material F. The discharge gap portion 100 (discharge portion 100) is maintained at atmospheric pressure or a pressure in the vicinity thereof, the processing gas G is supplied from the processing gas supply portion 30, and plasma discharge is performed in the discharge portion 100. The substrate F supplied from the previous process or the former winding roll is brought into close contact with the roll electrode 10A by the guide roll 20 and is rotated and transferred in synchronism, and is plasma by the processing gas at atmospheric pressure or a pressure in the vicinity thereof at the discharge unit 100. Discharge treatment is performed. It is preferable that the processing gas supply unit 30 has a slit shape that is the same as or slightly wider than the width of the base material F. Alternatively, pipe-shaped air outlets are arranged side by side to be equal to the width of the base material F. It may be arranged in. It is preferable that the processing gas G is introduced into the discharge unit 100 at a uniform flow rate or flow rate throughout the width direction. The substrate F once processed passes through folding rolls (also referred to as U-turn rolls) 11A, 11B, 11C and 11D, is transferred in the reverse direction, is held by the roll electrode 10B, and is again subjected to plasma discharge treatment in the discharge unit 100. It is taken up via the guide roll 21 or transferred to the next step (none is shown). The treated gas G ′ is accommodated in the gas exhaust means 40 and discharged to the outside.

[Roll electrode]
Next, roll electrodes 10A and 10B used in the present embodiment will be described. The roll electrodes 10A and 10B are made of a conductive base material such as metal, and it is desirable that the surface thereof be covered with a solid dielectric. Examples of the solid dielectric include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, silicon dioxide, aluminum oxide, zirconium oxide, metal oxides such as titanium oxide, and composite metal oxides such as barium titanate. it can. Particularly preferred is a ceramic-coated dielectric that has been ceramic-sprayed and then sealed with an inorganic material. In addition, examples of the conductive base material such as a metal of the electrode include metals such as silver, platinum, stainless steel, aluminum, and iron. Stainless steel is preferable from the viewpoint of processing. As the lining material, silicate glass, borate glass, phosphate glass, germanate glass, tellurite glass, aluminate glass, vanadate glass, etc. are preferable. Of these, borate glass is more preferably used because it is easy to process.

  It is desirable to adjust the temperature of the electrode used in this embodiment, such as heating or cooling, as necessary. For example, a liquid is supplied into the roll to control the temperature of the electrode surface and the temperature of the substrate F. As the liquid that gives temperature, an insulating material such as distilled water or oil is preferable. Although the temperature of the base material F changes with process conditions, it is usually preferable to set it as room temperature-200 degreeC, More preferably, it is set as room temperature-120 degreeC.

  The surface of the roll electrode is required to have high smoothness because the base material F adheres and the base material F and the electrode are transferred and rotated in synchronization. The smoothness is expressed as the maximum surface roughness height (Rmax) and centerline average surface roughness (Ra) defined in JIS B 0601. Rmax of the surface roughness of the belt electrode and roll electrode used in the present embodiment is preferably 10 μm or less, more preferably 8 μm or less, and particularly preferably 7 μm or less. Further, Ra is preferably 0.5 μm or less, and more preferably 0.1 μm or less.

  In the present embodiment, the distance b of the discharge unit 100 is determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using plasma, the shape of the electrode, and the like. The distance between the electrode surfaces is preferably from 0.1 to 20 mm, more preferably from 0.1 to 5 mm, and particularly preferably from 0.1 mm to 2 mm, from the viewpoint of uniformly generating plasma discharge. The discharge part 100 in this Embodiment means the space | interval which the electrode surface which opposes mutually approaches most. In the case of a roll electrode, it is desirable that the gap be constant with the rotation of the roll electrode. Specifically, the fluctuation of the gap between the rolls when the roll rotates once is preferably less than ± 30%, preferably less than ± 10%, more preferably less than ± 5%, and most preferably. Is ± 0. The variation in the width direction of the base material of the discharge unit 100 is the same as described above. 10-1000 mm is preferable and, as for the diameter of roll electrode 10A, 10B, 20-500 mm is more preferable. Moreover, the peripheral speed of a roll electrode is 1-100 m / min, More preferably, it is 5-50 m / min.

In this embodiment mode, the treatment chamber for performing plasma discharge is preferably surrounded by an electrode and a frame or container made of an insulating material, and a metal chamber may be used as long as insulation from the electrode can be obtained. For example, as a metal thing, the thing which stuck polyimide resin etc. on the inner surface of the frame of aluminum or stainless steel may be used, and the metal frame may be subjected to ceramic spraying to give insulation. It is also preferable to surround the entire apparatus with a processing container made of Pyrex (registered trademark) glass. Instead of such an outer enclosure, it is also possible to locally surround the side surfaces of the discharge part, the electrode, the substrate conveying means, etc., so that the processing gas can be appropriately supplied to the discharge part and the exhaust gas can be exhausted. Therefore, the gas concentration and composition can be made constant, and the plasma discharge treatment can be performed stably, which is preferable.
Means for applying a voltage for generating plasma discharge in the present invention is not particularly limited, but as one method, a power source is connected to one electrode of the counter electrode, and a ground is grounded to the other electrode, Apply voltage. As the power source in the present invention, a high frequency power source is preferably used. Or a pulsed power supply can be used. The value of the voltage applied to the electrode from the power source by applying a voltage is appropriately determined. For example, the voltage is preferably about 0.5 to 10 kV, and the power frequency is adjusted to 1 kHz to 150 MHz. If it is more than 13.56 MHz, a uniform thin film can be obtained by stable discharge. The waveform may be a pulse wave or a sine wave.
As another aspect, as disclosed in Japanese Patent Application Laid-Open No. 2004-189958, a plasma discharge may be generated by applying a high-frequency voltage to each of the facing roll electrodes.

[Processing gas]
A processing gas used in the plasma discharge processing apparatus of this embodiment will be described.

  In the present embodiment, it is particularly preferable to use a mixed gas of an inert gas and a reactive gas as the processing gas.

  Examples of inert gas elements useful in this embodiment include nitrogen and Group 18 elements of the periodic table, specifically nitrogen, helium, neon, argon, krypton, xenon, radon, and the like. In the present embodiment, nitrogen, helium and argon are preferable, and nitrogen is particularly preferable. The concentration of the inert gas in the processing gas is preferably 90% by volume or more in order to generate stable plasma. 90-99.99 volume% is especially preferable. The inert gas is necessary for generating plasma discharge, and the reactive gas in the plasma discharge is ionized or radicalized to contribute to the surface treatment.

  In the present embodiment, various substances are used as the reactive gas depending on the type of functional thin film produced on the substrate. For example, it is possible to form a low refractive index layer or an antifouling layer useful for an antireflection layer or the like by using an organic fluorine compound as a reactive gas, and it is useful for an antireflection layer or the like by using a silicon compound. A low refractive index layer or a gas barrier layer can also be formed. Further, by using an organometallic compound containing a metal such as Ti, Zr, Sn, Si, or Zn, a metal oxide layer, a metal nitride layer, or the like can be formed. These can form a medium refractive index layer or a high refractive index layer useful for an antireflection layer or the like, and can further form a conductive layer or an antistatic layer.

  Thus, organic fluorine compounds and metal compounds can be preferably cited as reactive gas substances useful in the present embodiment.

  As the organic fluorine compound of the reactive gas that is preferably used in the present embodiment, a gas such as fluorocarbon or fluorohydrocarbon is preferable. For example, fluorocarbon compounds such as tetrafluoromethane, hexafluoroethane, 1,1,2,2-tetrafluoroethylene, 1,1,1,2,3,3-hexafluoropropane, hexafluoropropene, etc. Can be, but is not limited to. It is preferable to select a compound that does not generate corrosive gas or harmful gas by plasma discharge treatment as the organic fluorine compound, but it is also possible to select a condition in which they are not generated. When an organic fluorine compound is used as a reactive gas useful in the present embodiment, it is preferable that the organic fluorine compound is a gas at normal temperature and normal pressure as it can be used as it is as the most suitable reactive gas component for achieving the purpose. . On the other hand, in the case of a liquid or solid organic fluorine compound at room temperature and normal pressure, it may be used after being vaporized by means of a vaporizer such as heating or decompression, or dissolved or sprayed in an appropriate organic solvent. You may evaporate and use.

  When using the above organic fluorine compound in the processing gas, the content of the organic fluorine compound in the processing gas is 0.01 to 10% by volume from the viewpoint of forming a uniform thin film on the substrate by plasma discharge treatment. Although it is preferable, it is 0.1 to 5 volume% more preferably. These may be used alone or in combination.

  The reactive gas metal compounds preferably used in the present embodiment include Al, As, Au, B, Bi, Ca, Cd, Cr, Co, Cu, Fe, Ga, Ge, Hg, In, and Li. , Mg, Mn, Mo, Na, Ni, Pb, Pt, Rh, Sb, Se, Si, Sn, V, W, Y, Zn, Zr, and other metal compounds or organometallic compounds, Al, Ge, In, Sb, Si, Sn, Ti, W, Zn or Zr is preferably used as the organometallic compound.

  In order to introduce the organometallic compound into the discharge part, any of gas, liquid or solid may be used at normal temperature and pressure, but when it is liquid or solid, What is necessary is just to vaporize and use by means, such as vaporization apparatuses, such as heating, pressure reduction, or ultrasonic irradiation. In the present embodiment, it is preferable to use it as a gas after vaporization or evaporation. If the boiling point of the liquid organometallic compound at room temperature and normal pressure is 200 ° C. or less, vaporization can be facilitated, which is suitable for manufacturing the thin film according to this embodiment. Further, when the organometallic compound is a metal alkoxide such as tetraethoxysilane or tetraisopropoxytitanium, it is easily soluble in an organic solvent, so that it may be diluted with an organic solvent such as methanol, ethanol, or n-hexane. Good. An organic solvent may be used as a mixed solvent.

  In the present embodiment, when an organometallic compound is used as a reactive gas in a processing gas, the content in the processing gas is preferably 0.01 to 10% by volume, more preferably 0.1%. ~ 5% by volume. The above metal compounds may be used by mixing several kinds of the same or different metal compounds.

  Note that hydrogen, oxygen, nitrogen, nitrogen monoxide, nitrogen dioxide, carbon dioxide, ozone, and hydrogen peroxide are added to the inert gas as the reactive gas of the organic fluorine compound and organometallic compound as described above. 0.1-10 volume% may be mixed and used, and the hardness of a thin film can be remarkably improved by using in this way auxiliary.

  When the substrate of the present embodiment is a film having an antireflection layer, for example, an organosilicon compound is suitable for forming a low refractive index layer, and a titanium-based organometallic compound forms a high refractive index layer. Any of them is preferably used. Moreover, the refractive index can be controlled by adjusting the mixing ratio using a gas in which these are mixed, so that a medium refractive index layer can be obtained.

  The low refractive index layer and the high refractive index layer formed by plasma discharge treatment using the above processing gas are thought to be mainly composed of metal oxides, if not all. For example, in a laminate of a low refractive index layer made of an organic silicon compound and a high refractive index layer made of an organic titanium compound, the low refractive index layer has silicon oxide and the high refractive index layer has titanium oxide as a main component. It is preferable. At this time, a small amount of silicon oxide may be mixed in the high refractive index layer mainly composed of titanium oxide, and conversely, a small amount of titanium oxide may be mixed in the low refractive index layer mainly composed of silicon oxide. Also good. By such mixing, the adhesion (adhesiveness) of each layer can be improved. Of course, an organic metal compound or fluorine-containing compound other than the main component can be mixed and added to the processing gas for adjusting the refractive index to the desired purpose or for other purposes, and the processing gas is supplied from the processing gas supply unit. It is preferable to mix appropriately at the stage before supply. As described above, the discharge portion is filled with the processing gas, and even if the entrained air slightly enters the processing chamber, the influence of a minute amount of air (oxygen or nitrogen) or moisture can be ignored in practice. Depending on the processing conditions, there may be a case where the processing gas is intentionally added with air (oxygen or nitrogen) or moisture.

〔Base material〕
Next, the base material according to the present embodiment will be described.

  Examples of the substrate according to this embodiment include a cellulose ester film, a polyester film, a polycarbonate film, a polystyrene film, a polyolefin film, a polyvinyl alcohol film, a cellulose film, and other resin films.

  A film obtained by appropriately mixing these film materials can also be preferably used. For example, a film obtained by mixing a commercially available resin such as ZEONEX (manufactured by Nippon Zeon Co., Ltd.) or ARTON (manufactured by Nippon Synthetic Rubber Co., Ltd.) can also be used. In addition, even for materials having a high intrinsic birefringence such as polycarbonate, polyarylate, polysulfone or polyether sulfone, the conditions such as solution casting or melt extrusion, and further the conditions for stretching in the vertical and horizontal directions, etc. By appropriately setting, a substrate suitable for the present embodiment can be obtained. In this Embodiment, it is not limited to the film of said description.

  As the thickness of the substrate suitable for the plasma discharge treatment of the present embodiment, a film of about 10 to 1000 μm can be preferably used, more preferably 10 to 200 μm, and particularly a thin substrate of 10 to 60 μm. Can be preferably used.

[Thin films, laminates and films]
In the present embodiment, the thin film is formed by performing plasma discharge treatment with the above processing gas at a discharge portion in the gap between the counter electrodes under atmospheric pressure or in the vicinity thereof. In the plasma discharge treatment under the atmospheric pressure or the pressure in the vicinity thereof in the present embodiment, a substrate having a very wide width of, for example, 2000 mm can be performed, and the treatment speed is 100 m / min. It can also be done. In this embodiment, when plasma discharge is started, first, a processing gas or an inert gas is introduced into the processing chamber while drawing the air in the processing chamber with a vacuum pump, and after replacing the air, the processing gas is discharged into the discharge section. Is preferably supplied to fill the discharge part. Thereafter, the substrate is transferred to carry out processing.

  The film thickness can be appropriately adjusted according to the discharge part, the processing gas concentration, and the conveyance speed of the substrate.

  Although the thin film formed on the substrate is only on one side by the plasma discharge treatment of the present embodiment, after winding, the opposite side may be passed through the apparatus for plasma discharge treatment. When the antistatic layer is formed of a metal oxide, the antistatic layer or the conductive layer is formed by applying a coating liquid such as metal oxide fine particles or crosslinked cationic polymer particles into a layer having a thickness of about 0.1 to 2 μm. Although it can be formed by coating, a thin conductive layer can also be formed by the plasma discharge treatment of this embodiment mode. For example, a conductive layer of metal oxide such as tin oxide, indium oxide, or zinc oxide may be formed. Further, easy adhesion processing described in Japanese Patent Application No. 2000-273066, antistatic processing described in Japanese Patent Application No. 2000-80043, and the like can be performed using the plasma discharge processing of the present embodiment.

  When forming the thin film of the present embodiment, it is easy to form a uniform thin film by performing a plasma discharge treatment after previously heat-treating the substrate at 50 to 120 ° C., and preheating is a preferable method. By performing the heat treatment, the substrate that has absorbed moisture can be dried, and it is preferable to perform a plasma discharge treatment while maintaining a low humidity. It is preferable to perform plasma discharge treatment without absorbing moisture on a substrate conditioned at less than 60% RH, more preferably 40% RH. The moisture content is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less.

  Moreover, the thin film can be stabilized by heat-treating the substrate after the plasma discharge treatment in a heat treatment zone at 50 to 130 ° C. for 1 to 30 minutes, which is an effective means.

Furthermore, when producing a laminated body by the multistage plasma discharge process which concerns on this Embodiment, you may irradiate an ultraviolet-ray to a process surface before and after each plasma discharge process, and the adhesiveness to the base material of the formed thin film ( Adhesiveness) and stability can be improved. Preferably as the ultraviolet irradiation amount is 50~2000mJ / cm ^2, the effect is not sufficient at less than 50 mJ / cm ^2, there is a fear that deformation occurs in exceeds 2000 mJ / cm ² substrate.

  The thickness of the thin film formed in this embodiment is preferably in the range of 1 to 1000 nm.

  The film thickness deviation with respect to the average film thickness of the thin film formed by the plasma discharge treatment of this embodiment is small, and a uniform thin film can be formed, which is an excellent thin film forming method. A film thickness deviation of ± 10% can be easily obtained, and a uniform thin film preferably within ± 5%, particularly within ± 1% can be obtained.

  The composition coating solution containing inorganic or organic fine particles described above is applied to a substrate and dried, and the surface is formed on a functional layer having an uneven surface with an Ra of about 0.1 to 0.5 μm, such as an antiglare layer. A thin film having a uniform thickness can also be formed by the discharge treatment. For example, when the thin film is a low refractive index layer or a high refractive index layer, it can be provided as an optical interference layer.

  The film of this embodiment is composed of a thin film formed by the plasma discharge treatment of this embodiment and a laminate thereof.

  Examples of the film of the present embodiment include an antireflection film, an antiglare antireflection film, an electromagnetic wave shielding film, a conductive film, an antistatic film, a retardation film, an optical compensation film, a viewing angle widening film, a brightness enhancement film, and the like. Although there is, it is not limited to these.

[Gas supply means]
Next, the processing gas discharge means of the present invention will be described with reference to FIG. 1 and FIG.

  FIG. 2 shows a case where the processing gas G supplied from the nozzle portion 301 of the processing gas discharge means 30 passes through the covering space portions 302A and 302B that are the gap portions between the roll electrodes 10A and 10B and the processing gas discharge means 30. The flow and the flow when passing through the discharge gap 100 (discharge unit 100) are schematically shown.

  In FIG. 2, when the processing gas G supplied from the nozzle unit 301 passes through the discharge unit 100, the narrowest part of the discharge unit 100 becomes a bottleneck and the entire amount cannot pass through the discharge unit 100, and a part of it flows backward. To the covering space portions 302A and 302B between the roll electrodes 10A and 10B and the processing gas discharge means 30. The processing gas G that has entered the covering space portions 302A and 302B is not vaporized, but floats as particles (fine powder). The particles gradually accumulate on the electrode surface and the surface of the substrate to be treated with the treatment time, and further mixed into the film formation of the substrate, thereby deteriorating the film quality (haze) of the thin film. Furthermore, since the discharge state changes when particles are scattered in the reaction vessel including the electrode surface, and as a result, it becomes difficult to perform stable treatment and film formation, the entire amount of the processing gas G passes through the discharge unit 100. It becomes necessary to do. For that purpose, it is desirable that there are as few obstacles (resistance) as possible in the path through which the processing gas G passes.

  When the flow resistance value of the gas received when the processing gas G passes through the coating space portions 302A and 302B is Pa and the flow resistance value of the gas received when passing the discharge portion 100 is Pb, the processing gas G is In order not to go into the covering space portions 302A and 302B, it is necessary to increase Pa.

Here, the flow resistance value Pa is generally expressed by the equation (1).
P = (3 × Q × μ × L) / (2 × B ³ × W) = K × L / B ³ ... (1)
Q: Fluid flow rate μ: Fluid viscosity L: Slit length (r2 × θ in this embodiment)
B: Slit thickness (r2-r1 in this embodiment)
W: Slit width (length of roll electrode)
K: coefficient when Q, μ, and W are constant, where r1 is the radius of the roll electrode, r2 is the distance from the center of rotation of the roll electrode to the processing gas supply means, and θ is the coating space 302 (slit length L) And the rotation center of the roll electrode, schematically shown in FIG.

  Equation (1) indicates that the flow resistance value P is proportional to the slit length L and inversely proportional to the cube of the slit thickness B.

To increase Pa, 1) decrease B or increase L.
2) Increase the resistance of the flow path through which the fluid passes (lower the flow rate Q).
3) Increase fluid viscosity μ (increase fluid temperature).
That is.
<Example>
Table 1 shows the results of an experimental investigation on the relationship between the slit width B and the slit length L with respect to 1) above.

That is, the distance b of the discharge part 100 is 0.1 ≦ b ≦ 2.0, and θ is
π / 18 ≦ θ
It was found that no film surface powder was generated under the above conditions.
Further, regarding particle generation and film haze generation, the relationship between the ratio Pa / Pb of the resistance values Pa and Pb received by the gas and the exhaust flow rate of the gas was examined, and the results are shown in Table 2.

In Tables 1 and 2, ◯ indicates that there is no problem, and X indicates that the level is defective.
Here, B is the gap width shown in FIG. 3, and b is the dimension of the discharge part 100.
In Table 1, the resistance value Pa of the flow received by the processing gas G is larger than the resistance value Pb when it occurs when passing through the discharge part 100, and the gas exhaust flow rate of the gas flowing into the gas discharging means is the processing gas discharging means. When the gas supply flow rate is larger than this, fine particles (particles) are not mixed in the film formation, and the film quality (haze) of the thin film is at a level that causes no problem.
That is, 1 <Pa / Pb
Is desirable for particle adhesion and film haze.
In Comparative Example 1, when the exhaust flow rate was smaller than the gas supply amount, the film haze was poor with respect to the deterioration of the film haze. Further, as shown in Comparative Example 2, when Pa / Pb = 0.5 and the exhaust gas flow rate is small, particle non-adherence occurs, and the film haze is not good.
With respect to increasing the resistance value of the flow path, the flow rate of the gas supplied from the processing gas supply unit is Qin, and the exhaust gas flow rate ratio (Qout / Qin) when the flow rate of the gas exhausted in the exhaust gas exhaust means is Qout, Particle generation and film haze deterioration were visually determined. At this time, according to the experiment, 1 <Qout / Qin
Then, there was no problem with respect to particle adhesion and film haze. But further
2 ≦ Qout / Qin ≦ 10
Was a more desirable exhaust flow rate ratio.
Next, as a means for increasing the resistance value of the flow path through which the gas is exhausted, a method of increasing the surface roughness of the flow path through which the gas passes is used. In the present embodiment, the unevenness of the surface facing the coating space portions 302A and 302B of the processing gas discharge means 30 is expressed as a distance Hb1 from the surface RH to the convex portion of the roll electrode and a distance Hb2 from the surface RH to the concave portion. (See FIG. 4). Table 3 shows the relationship between the ratio Hb1 / Hb2 and the film surface powder (particles) adhering to the film surface.

From Table 3, Hb1 / Hb2 ≦ 0.5
Then, it was experimentally determined that powder (particles) hardly adhere to the film surface. In the table, ◯ indicates a level where there is no problem, and Δ indicates a level where there is a slight problem but it is not defective.
3) Resistance control by gas temperature As the temperature rises, the gas viscosity increases and the gas flow resistance changes. That is, when the temperature of the processing gas is Ta ° C. and the processing gas temperature in the gap where the pair of roll electrodes discharge is Tb ° C., Table 4 is obtained.

From Table 4, 1 <Ta / Tb
That is, when the temperature of the processing gas is higher than the temperature of the gas passing between the counter electrode rolls, powder (particles) is less likely to adhere to the film surface. In the table, x indicates that it is defective.

The conditions common to the examples are as follows.
<Evaluation of particle adhesion>
The particle adhesion was evaluated visually with the naked eye or visually with a microscope.
<Haze>
Haze was measured according to ASTM-D1003-52.
<Base film>
A polyethylene terephthalate film (PET) having a substrate thickness of 128 μm was used.
<Film formation conditions>
<Processing gas 1>
Discharge gas: 94.9% by volume of nitrogen
Thin film forming gas: Raw material gas: Tetraethoxysilane (mixed with nitrogen gas and vaporized by a vaporizer manufactured by Lintec Corporation) 0.1% by volume
Reaction gas: Oxygen gas 5.0% by volume
<Processing gas 2>
Discharge gas: Nitrogen gas 97.9% by volume
Thin film forming gas: tetraisopropoxy titanium 0.1% by volume
Additive gas: 2.0% by volume of hydrogen
<Auxiliary gas>
Nitrogen 100% by volume
<Power supply conditions>
1st electrode side frequency 80kHz
Output density 5W / cm ²
Second electrode side frequency 13.56MHz
Output density 5W / cm ²
<Roll electrode>
Roll diameter: φ300mm
From the above, in the thin film forming method by atmospheric pressure plasma discharge, the thin film forming apparatus in which the gas flow resistance and the flow rate of supply and exhaust are adjusted so that suspended fine particles are not mixed in the film formation of the substrate, and A thin film forming method could be provided.

That is,
The ratio between the flow resistance Pa generated when the processing gas G passes through the coating space portions 302A and 302B and the flow resistance Pb generated when the processing gas G passes through the discharge portion 100 is
1 <Pa / Pb
And
And the ratio of the gas exhaust flow rate Qout in the exhaust gas discharge means and the gas supply flow rate Qin in the processing gas discharge means 30 is:
1 <Qout / Qin
It is preferable that 10 ≦ Pa / Pb ≦ 1000,
2 ≦ Qout / Qin ≦ 10
Be.
And the gas exhaust flow rate Qout, is the ratio between the front Kiga scan discharge flow rate Qin,
2 ≦ Qout / Qin ≦ 10
Be.
The distance b of the discharge part 100 is 0.1 ≦ b ≦ 2.0 (mm), or the angle θ from the center of the roll electrode shown in FIG. 2 is π / 18 ≦ θ,
That at least one of the above is true.
The surfaces facing the coating space portions 302A and 302B of the processing gas discharge means have uneven rough surfaces, the distance Hb1 from the surface RH to the convex portion of the roll electrodes 10A and 10B, and the distance Hb2 from the surface RH to the concave portion. And the ratio of Hb1 / Hb2 ≦ 0.5.
It has a mechanism for applying heat to the coating space portions 302A and 302B, and includes a temperature Ta of the processing gas G when the processing gas G passes through the coating space portion and a processing gas temperature Tb when the processing gas G passes through the discharge portion 100. The ratio is 1 ≦ Ta / Tb.
Is to satisfy.

Claims (12)

A thin film forming apparatus for forming a thin film by performing plasma discharge treatment on the surface of a substrate to be continuously transferred under atmospheric pressure or a pressure in the vicinity thereof,
A pair of roll electrodes facing and rotating with a predetermined gap;
Plasma discharge means for generating a plasma discharge by applying a voltage to the pair of roll electrodes;
Transfer means for transferring the substrate to the plasma discharge means;
A processing gas discharge means for discharging a processing gas in the direction of the predetermined gap to the base material passing through the plasma discharge means;
Gas discharge means for discharging the gas after the processing gas has passed through the plasma discharge means;
Between the processing gas discharge means and the surface of the pair of roll electrodes, a coating space portion having a certain space in the axial direction along the surface of the roll electrode;
Have
The process gas comprises a flow resistance Pa experienced when passing in front Symbol covering space, said pair of rolls electrodes, and the flow resistance Pb experienced when passing through the predetermined gap, the ratio of,
1 <Pa / Pb
And
And the ratio of the gas exhaust flow rate Qout of the exhaust gas taken in by the gas discharge means and the gas discharge flow rate Qin of the gas from which the processing gas discharge means discharges the processing gas is:
1 <Qout / Qin
A thin film forming apparatus characterized by the above. The process gas comprises a Re before Symbol flow resistance Pa, said the flow resistance Pb, the ratio of,
10 ≦ Pa / Pb ≦ 1000
The thin film forming apparatus according to claim 1 , wherein: And the gas exhaust flow rate Qout, is the ratio between the front Kiga scan discharge flow rate Qin,
2 ≦ Qout / Qin ≦ 10
The thin film forming apparatus according to claim 1 , wherein: Before Symbol pair of rolls electrodes, the distance b of the predetermined gap,
0.1 ≦ b ≦ 2.0 (mm)
Or
The arc viewed from the axial direction of the covering space portion has an angle θ from the center of the roll electrode,
π / 18 ≦ θ
Being
The thin film forming apparatus according to claim 1 , wherein at least one of the following holds: Surface facing the coating space portion of the process gas discharging means has a rough surface that is concave convex, the distance Hb1 from the surface RH of the roll electrode to the convex portion, the distance Hb2 from the surface RH until recess The ratio of Hb1 / Hb2 ≦ 0.5
The thin film forming apparatus according to claim 1 , wherein: A mechanism for applying heat to pre-Symbol the covering space, and the temperature Ta of the process gas when the process gas passes through the coating space, the pair of rolls electrodes passes through the predetermined gap to be discharged The ratio of the processing gas temperature Tb to 1 ≦ Ta / Tb
The thin film forming apparatus according to claim 1 , wherein: A thin film forming method for forming a thin film by performing plasma discharge treatment under atmospheric pressure or a pressure in the vicinity thereof on the surface of a substrate to be continuously transferred,
A pair of roll electrodes facing and rotating with a predetermined gap;
A plasma discharge step of generating a plasma discharge by applying a voltage to the pair of roll electrodes;
A transfer step of transferring the substrate to the plasma discharge step;
A processing gas discharge step of discharging a processing gas in the direction of the predetermined gap to the base material passing through the plasma discharge step;
A gas discharge step of discharging the gas after the processing gas has passed through the plasma discharge step;
Between the process gas discharge step and the surfaces of the pair of roll electrodes, a covering space portion having a constant space in the axial direction along the surface of the roll electrodes;
Have
The ratio between the flow resistance Pa received when the processing gas passes through the coating space and the flow resistance Pb received when the processing gas passes through the predetermined gap between the pair of roll electrodes is:
1 <Pa / Pb
And
And the ratio of the gas exhaust flow rate Qout of the exhaust gas taken in by the gas discharge step and the gas discharge flow rate Qin of the gas from which the processing gas discharge step discharges the processing gas is:
1 <Qout / Qin
A method for forming a thin film, characterized in that The process gas has a ratio of the flow resistance Pa to the flow resistance Pb.
10 ≦ Pa / Pb ≦ 1000
The thin film forming method according to claim 7 , wherein: The ratio of the gas exhaust flow rate Qout and the gas discharge flow rate Qin is:
2 ≦ Qout / Qin ≦ 10
The thin film forming method according to claim 7 , wherein: The distance b between the predetermined gaps of the pair of roll electrodes is
0.1 ≦ b ≦ 2.0 (mm)
Or
The arc viewed from the axial direction of the covering space portion has an angle θ from the center of the roll electrode,
π / 18 ≦ θ
Being
The method for forming a thin film according to claim 7 , wherein at least one of the following holds: The surface facing the coating space portion of the process gas discharge step has a rough surface that is uneven, a distance Hb1 from the surface RH to the convex portion of the roll electrode, and a distance Hb2 from the surface RH to the concave portion, The ratio of Hb1 / Hb2 ≦ 0.5
The thin film forming method according to claim 7 , wherein: A mechanism for applying heat to the coating space, and a temperature Ta of the processing gas when the processing gas passes through the coating space, and a time when the pair of roll electrodes pass through the predetermined gap The ratio of the processing gas temperature Tb is 1 ≦ Ta / Tb
The thin film forming method according to claim 7 , wherein:

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