JP3335603B2 - Discharge plasma thin film manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge plasma thin film manufacturing apparatus for forming a thin film on a substrate using discharge plasma.

[0002]

2. Description of the Related Art Conventionally, a method of forming a thin film using plasma generated by glow discharge under a low pressure condition has been put to practical use. Also, various methods for generating discharge plasma under a pressure near the atmospheric pressure (for example, normal pressure plasma CVD) have been proposed.

As an electrode for generating a discharge plasma, there is an electrode of a single metal such as copper or stainless steel, or an electrode having a surface of a metal electrode coated with a solid dielectric having a high relative dielectric constant. In this case, discharge plasma can be stably generated. Aluminum oxide or the like is used as the solid dielectric.

When an electrode surface is coated with a solid dielectric,
If the gas conditions for film formation are the same, the discharge current value with respect to the applied voltage changes depending on the relative dielectric constant of the solid dielectric,
It is preferable to increase the relative dielectric constant in order to lower the applied voltage or increase the film formation rate. However, the relative dielectric constant of the solid dielectric varies depending on the material and the thickness. When a higher relative dielectric constant is to be obtained, the thickness may be increased, but the cost increases. Also, if the solid dielectric is too thick,
Cracks may occur.

[0005] Materials having a high relative dielectric constant include zirconium dioxide and barium titanate. When these materials are coated on the electrode surface, the surface roughness becomes coarser than that of aluminum oxide. Plasma C
In VD, when a thin film is continuously formed on one surface of a film while sliding the film on the surface of an electrode such as a roll electrode, the film may be damaged.

The relative dielectric constant of aluminum oxide is 7 to
About 14, the relative dielectric constant of barium titanate is about 200,
The relative dielectric constant of zirconium dioxide is about 9 to 20.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a high relative dielectric constant of a solid dielectric formed on an electrode surface of a counter electrode and a small surface roughness. It is an object of the present invention to provide a discharge plasma thin film manufacturing apparatus which is excellent in slipperiness and smoothness of an electrode surface, can achieve a high film formation rate, and has a low possibility of damaging a base material when performing continuous film formation.

[0008]

The discharge plasma thin film manufacturing apparatus of the present invention generates a discharge plasma by applying an electric field between opposed electrodes in a mixed gas atmosphere, and uses the discharge plasma to form a discharge plasma on a substrate. In a thin film manufacturing apparatus for forming a thin film, a solid dielectric composed of a barium titanate (BaTiO3) layer or a zirconium dioxide (ZrO2) layer and an aluminum oxide (Al2 O3) layer is formed on at least one electrode surface of a counter electrode. , Characterized by being laminated with the aluminum oxide layer as a surface layer.

According to the apparatus for manufacturing a discharge plasma thin film of the present invention, a barium titanate layer or a zirconium dioxide layer is laminated on the first layer to increase the relative dielectric constant of the solid dielectric, and the second layer (surface layer) is made of carbon dioxide. Since the aluminum layer is laminated to improve the smoothness and smoothness of the surface, it is possible to increase the film forming speed and to reduce the possibility that the substrate is damaged when performing continuous film forming.

In the apparatus for producing a discharge plasma thin film according to the present invention, it is preferable that the barium titanate layer or the zirconium dioxide layer and the aluminum oxide layer are laminated by thermal spraying.

When the surface aluminum oxide layer is laminated by thermal spraying, the surface roughness of the aluminum oxide layer can be reduced to 0.1 μm Ra or less by polishing the surface of the aluminum oxide layer. The surface roughness can be considerably reduced as compared with the case of spraying (surface roughness: about 1 μmRa).

In the apparatus for producing a discharge plasma thin film of the present invention, the thickness of the solid dielectric composed of a barium titanate layer or a zirconium dioxide layer and an aluminum oxide layer is preferably 0.05 to 4 mm. If the thickness of the solid dielectric exceeds 4 mm, a high voltage is required to generate discharge plasma. If the thickness is less than 0.05 mm, dielectric breakdown occurs when a voltage is applied, and arc discharge occurs. If the thickness of the solid dielectric is too small, cracks may occur depending on the shape and temperature of the electrode.

In the apparatus for manufacturing a discharge plasma thin film according to the present invention,
A method of forming a film using plasma generated by glow discharge in a mixed gas atmosphere such as Ar or N2 gas under a low pressure condition in a vacuum vessel, or discharge plasma in a mixed gas atmosphere under a pressure near atmospheric pressure Any of the continuous film forming methods (for example, discharge plasma CVD) for performing the treatment by generating the gas may be applied.

Here, in both the film formation under low pressure conditions and the film formation under a pressure near the atmospheric pressure, a discharge plasma is generated by applying a voltage between the opposing electrodes.
When the atmosphere in the discharge space is set at a pressure close to the atmospheric pressure, there is a point that it is difficult for the discharge to start compared to the case under the low pressure condition.However, the distance between the electrodes is reduced, and a pulsed electric field is applied. By doing so, stable discharge plasma can be generated even under a pressure near the atmospheric pressure. Here, the pressure near the atmospheric pressure means a pressure of 13300 to 106400 Pa.

As the counter electrode used in the discharge plasma thin film forming apparatus of the present invention, a single metal such as copper and aluminum,
Examples include those made of alloys such as stainless steel and brass.

The counter electrode preferably has a structure in which the distance between the counter electrodes is constant in order to avoid the occurrence of arc discharge due to electric field concentration during film formation under a pressure near atmospheric pressure. Examples of an electrode structure that satisfies this condition include a parallel plate type, a cylindrical opposed plate type, a spherical opposed plate type, a hyperboloid opposed plate type, and a coaxial cylindrical structure.

The distance between the opposed electrodes is determined by the thickness of the solid dielectric
It is determined in consideration of the material, the magnitude of the applied voltage, the purpose of using the discharge plasma, and the like.
It is preferably 0 mm. If it is less than 1 mm, the distance between the electrodes is too small, and it is difficult to arrange (run) the base material between the electrodes. If it is more than 50 mm, it is difficult to generate uniform discharge plasma.

As the mixed gas used in the apparatus for producing a discharge plasma thin film of the present invention, a mixed gas comprising a source gas, a reaction gas and a diluent gas is suitable. The content ratio of the source gas in the mixed gas is preferably 0.01 to 5% by volume.

The raw material gas is a gas that is a raw material of a thin film to be formed on a base material, for example, tetramethoxysilane,
Reactive organic silicon compounds such as tetraethoxysilane, methyltriethoxysilane, tetramethylsilane and tetraethylsilane; reactive organic titanium compounds such as titanium isopropoxide and titanium butoxide;
), Carbon hexafluoride (C2F6), propylene hexafluoride (CF3CFCF2), and cyclooctafluoride (C4F6).
8) Fluoro-carbon compounds such as
Reactive fluorine compounds such as halogen-carbon compounds such as ClF3) and fluorine-sulfur compounds such as sulfur hexafluoride (SF6).

The above-mentioned reaction gas reacts with a raw material gas to produce a compound constituting a target thin film or facilitates its production. Examples of the reaction gas include oxygen gas, ozone, water (steam), Organic compounds containing elemental oxygen, such as carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aldehydes such as methanal and ethanal, nitrogen Gas, ammonia, sulfur dioxide, sulfur trioxide and the like. The content ratio of the reaction gas in the mixed gas is preferably from 0 to 99.99% by volume.

The diluent gas is used to control the degree of reaction between the raw material gas and the reaction gas and the properties of the formed inorganic thin film. For example, helium, argon, neon, nitrogen gas having a low activity is used. And the like. These may be used alone or in combination of two or more. The content ratio of the dilution gas in the mixed gas is 0 to 9
9.99% by volume is preferred.

When performing the discharge plasma CVD in the discharge plasma thin film manufacturing apparatus of the present invention, the discharge current density between the opposed electrodes is 0.2 to 300 mA in a gas atmosphere containing a metal compound under a pressure near the atmospheric pressure. / Cm ² is preferably applied. Under these conditions, when an antireflection film (metal-containing thin film) is formed on the surface-treated hard coat surface, a film quality equivalent to that of sputtering, which is another film formation method, can be obtained. Continuous film formation similar to the method of construction becomes possible.

The discharge current density is a value obtained by dividing the current flowing between the electrodes by the discharge by the area of the discharge space in the direction orthogonal to the current flow direction. For example, a parallel plate type counter electrode is used. In this case, it corresponds to a value obtained by dividing the current value by the facing area.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing the entire configuration of the embodiment of the present invention.

The discharge plasma thin film manufacturing apparatus shown in FIG.
It mainly comprises a chamber 1, a high-voltage pulse power supply 2, a processing gas supply device 3, a vacuum pump (oil rotary pump) 4, an unwind roll 5, a take-up roll 6, and the like.

Inside the chamber 1, a roll electrode 11 and a curved electrode 12 facing each other are provided with a predetermined gap (for example, 2 mm).
mm). A high-voltage pulse power supply 2 is provided between the roll electrode 11 and the curved electrode 12 (discharge space).
Is applied. In addition, the roll electrode 11
A hot water circulation channel (not shown) is formed inside the curved electrode 12, and the surface temperature of each electrode is controlled by the base material F.
(For example, 70 ° C.).

Sealing devices 7 and 8 are installed before and after the chamber 1 (before and after in the running direction of the base material F). Further, a gas nozzle 13 for blowing and a gas nozzle 1 for suction are provided before and after the roll electrode 11 in the chamber 1.
The processing gas supply device 3 is connected to the blowing gas nozzle 13, and the suction gas nozzle 14 is provided.
Is connected to a vacuum pump 4 for reducing pressure.

As shown in the front view (A) and the longitudinal sectional view (B) of FIG.
The first chamber 21 includes a first chamber 21 and a second chamber 22 provided with the first chamber 1a. The first chamber 21 and the second chamber 22 are separated by a perforated plate 23. In the second room 22,
A gap plate 24 having a uniform gap is provided at the end, and a slit-shaped outlet 25 is formed near the edge, so that the gas flowing into the first chamber 21 through the gas inlet 21a is The gas flows into the second chamber 22 through the perforated plate 23, goes around the gap plate 24, and becomes a laminar flow from the slit-shaped outlet 25 and blows out into the discharge space.

The suction gas nozzle 14 has the same structure as the blowing gas nozzle 13.

In the apparatus for manufacturing a discharge plasma thin film having the above-described structure, in the processing gas supply device 3, the raw material: Si (OCH3) vaporized by the vaporizer (not shown).
4) is mixed with a carrier gas (N2, Ar and O2 gas), and the mixed processing gas is supplied at a predetermined flow rate from the blowing gas nozzle 13 between the roll electrode 11 and the curved electrode 12 (discharge space). While the suction gas nozzle 14
The discharge plasma can be generated by applying a high voltage from the high voltage pulse power supply 2 between the roll electrode 11 and the curved electrode 12 in this state,
By the generated discharge plasma, a SiO2 thin film can be continuously formed on the surface of the base material F running on the roll electrode 11.

The notable point of this embodiment is that
As shown in FIG. 3, on the surface of the roll electrode 11, a solid dielectric 110 composed of two layers of a barium titanate layer 111 and an aluminum oxide layer 112 (surface layer) each formed by thermal spraying is formed. The solid dielectric 110 has a two-layer structure as described above.
Can be increased, and the surface roughness of the surface in contact with the substrate F can be reduced.

Here, when the relative dielectric constants of the case where the solid dielectric is composed of two layers and the case where the solid dielectric is composed of a single layer are compared, for example, the thickness of the single-layer solid dielectric is 1.6 mm.
When the thermal spraying material is aluminum oxide, the relative dielectric constant becomes 7 to 8.5, but as in the present embodiment, the first layer is a barium titanate layer: 0.8 mm, and the second layer is In the case of a solid dielectric composed of two layers (a surface layer) of an aluminum oxide layer: 0.8 mm, the relative dielectric constant can be increased to about 20 to 30. As the relative dielectric constant increases, the plasma density increases and the discharge current increases at the same applied voltage, so that the deposition rate of the thin film can be increased.

In this embodiment, a solid dielectric (single layer) of aluminum oxide alone is provided on the surface of the curved electrode 12.
Is formed by thermal spraying, and the curved electrode 12 also has a barium titanate layer and an aluminum oxide layer (surface layer).
May be formed. If it is not necessary to provide a solid dielectric on both the roll electrode 11 and the curved electrode 12 due to film forming conditions and the like, a solid dielectric is formed only on the roll electrode 11 on the side where the substrate F contacts. .

Further, in the above embodiment, the solid dielectric 110 is composed of the two layers of the barium titanate layer 111 and the aluminum oxide layer 112. The combination of the two layers is a zirconium dioxide layer and an aluminum oxide layer. (Surface layer).

[0036]

EXAMPLES Examples of the present invention will be described below along with comparative examples. Example 1 In the discharge plasma processing apparatus shown in FIG. 1, a SiO2 thin film was formed on the surface of a substrate F under the following conditions. [Apparatus outline] Roll electrode (cathode): SUS304, radius 400m
m, width 760 mm (spray coating Al2 O3 (surface layer) /
BaTiO3: 0.8 mm / 0.8 mm) Curved electrode (anode): SUS304, radius 402 mm,
710 mm in width (sprayed coating Al2 O3: 1.6 mm) Gap between electrodes: 2 mm Length between electrodes: 160 mm Blowing gas nozzle: Two-chamber type (with temperature control, see Fig. 2) Suction gas nozzle: Same shape as blowing gas nozzle Power supply used: Power supply manufactured by Heiden Laboratories Liquid material vaporization supply device: manufactured by Nippon Pionics Co., Ltd. [Film formation conditions] Base material: PET thickness 80 μm (hard-coated product) Base material width: 710 mm Film formation material: Si (OCH3) 4 Carrier gas: N2 gas, Ar gas, O2 gas Gas flow rate: N2: 8 SLM, Ar: 34 SLM, O2:
8SLM Gas temperature: 80 ° C. Roll electrode temperature: 70 ° C. Curved electrode temperature: 70 ° C. Applied voltage Vp-p: 13 kV, 17 kV Pulse frequency: 4 kHz <Comparative Example 1> In Example 1, the thermal spray coating of the roll electrode was Al 2 O 3: An SiO2 thin film was formed on the surface of the substrate F in the same manner as in Example 1 except that the thickness was 1.6 mm (single layer).

The discharge characteristics of each of the above Examples 1 and Comparative Example 1, the results of evaluation of the physical properties (refractive index, film thickness) of the SiO2 thin film obtained by the treatment of each of the examples, and the roll electrode of each of the examples. Table 1 below shows the measurement results of the surface roughness.

However, the refractive index and the film thickness were measured by converting from a measured value of a reflectance curve of UV-3101PC manufactured by Shimadzu Corporation. The surface roughness was measured using a stylus type surface roughness meter. Further, with respect to the film forming speed, the film thickness at the applied voltage Vp-p = 13 kV of Comparative Example 1 was used as a reference (1).
(00%), the film thickness of each measurement result was converted into a film formation rate and shown as a percentage.

[0039]

[Table 1]

From the results shown in Table 1 above, the film forming speeds when the applied voltage Vp-p was 13 kV in Example 1 and when the applied voltage Vp-p was 17 kV in Comparative Example 1 were almost the same. ing. In addition, when the applied voltage Vp-p is the same, the film forming speed is higher in the first embodiment,
It can be seen that Example 1 is excellent in terms of the film forming speed and low voltage.

Here, when a film is formed by using Si (OCH3) 4 as a raw material, since the film is formed with an applied voltage of 17 kV or more because the reactivity is higher than that of TEOS (tetraethoxysilane), the surface of the film is formed. Although it became cloudy and powdery, in the case of Example 1, the applied voltage was 17
Even if the voltage is suppressed to kV or less, the film formation rate can be increased, and a high quality SiO2 thin film can be efficiently formed. <Embodiment 2> First, an experimental apparatus used in this embodiment 2 is shown in FIG. The experimental apparatus shown in FIG. 4 includes a parallel plate-type counter electrode 210 including an upper electrode 211 and a lower electrode 212.
It is installed in the chamber 201. The lower electrode 212 is grounded, so that a pulse electric field from the high voltage pulse power supply 202 connected to the upper electrode 211 can be applied between the opposing electrodes 210. Although not shown, a pump for reducing pressure and an N2 gas supply device are connected to the chamber 201, and the chamber 201 can be replaced with N2 gas.

In the second embodiment, in the experimental apparatus shown in FIG. 4, the upper electrode 211 and the lower electrode 212 are each made of stainless steel (SUS304), and the surface of the upper electrode 211 is made of aluminum dioxide (Al 2) as a solid dielectric. O3) is spray-coated with a thickness of 0.8 mm, and the surface of the lower electrode 212 is made of the material and material shown in Table 2 below.
The solid dielectric material was spray-coated under the thickness condition, and the discharge characteristics under these conditions were measured. Table 2 shows the results. The high-voltage pulse power supply 202 is a Heiden Labs X-pulse power supply, and the pulse electric field from the high-voltage pulse power supply 202 is applied between the opposing electrodes 210 (1 mm).
To generate a discharge plasma.

[0043]

[Table 2]

As is evident from the results in Table 2, it is possible to lower the firing voltage by changing the thermal spraying material. Further, even when the surface layer of the solid dielectric is made of Al 2 O 3,
When the lower layer is made of BaTiO3, the firing voltage can be reduced as compared with the case where the solid dielectric is a single layer of Al2 O3.

[0045]

As described above, according to the discharge plasma thin film manufacturing apparatus of the present invention, the relative dielectric constant of the solid dielectric formed on the counter electrode can be increased, so that the voltage applied between the counter electrodes can be reduced. If it is the same as the conventional case, the film formation rate can be increased, and a good quality thin film can be efficiently formed. Further, the raw material efficiency is improved by increasing the film forming speed. Further, the applied voltage can be reduced, and a highly reactive raw material can be formed. In addition, since an aluminum dioxide layer is stacked on the surface of the solid dielectric to improve the smoothness and smoothness of the surface, the possibility of damaging the substrate during continuous film formation is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an embodiment of the present invention.

FIG. 2 is a front view (A) and a longitudinal sectional view (B) of a blowing gas nozzle used in the embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a roll electrode used in the embodiment of the present invention.

FIG. 4 is a diagram schematically showing an apparatus used in Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chamber 2 High voltage pulse power supply 3 Processing gas supply device 4 Vacuum pump 5 Unwind roll 6 Take-up roll 7,8 Sealing device 11 Roll electrode 110 Solid dielectric 111 Barium titanate layer 112 Aluminum dioxide layer 12 Curved electrode 13 Blowing Gas nozzle 14 Gas nozzle for suction

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 C08J 7/00 C23C 26/00 H01L 21/205 H01L 21/31 H05H 1 / twenty four

Claims (2)

(57) [Claims] In a thin film manufacturing apparatus for generating a discharge plasma by applying an electric field between opposed electrodes in a mixed gas atmosphere and forming a thin film on a substrate using the discharge plasma, at least one of the opposed electrodes is provided. A discharge plasma thin film manufacturing apparatus, characterized in that a solid dielectric comprising two layers, a barium titanate layer or a zirconium dioxide layer and an aluminum oxide layer, is laminated on the electrode surface with the aluminum oxide layer as a surface layer. 2. The method according to claim 1, wherein the thickness of the solid dielectric comprising a barium titanate layer or a zirconium dioxide layer and an aluminum oxide layer is 0.05 to 4 mm. apparatus.