JP2001049443A - METHOD FOR FORMATION OF SiO2 THIN FILM UTILIZING DISCHARGE PLASMA - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a thin film in which the secular change of the film thickness and film quality of an SiO2 thin film formed by utilizing discharge plasma is suppressed. SOLUTION: When generating discharge plasma by applying the electric field to the space between counter electrodes under the pressure in the vicinity of the atmospheric pressure in a gaseous atmosphere contg. a silicon organometallic compd. in such a manner that the discharge electric current density is controlled to 0. 01 to 300 mA/cm2 to form a silicon organometallic compd.-conty. thin film, the concn. of the silicon organometallic compd. in the gaseous atmosphere is regurated to be 0. 01 to 0. 2 vol.%, and the electric field intensity to be 65 to 150 kV/cm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, in a gas atmosphere containing a silicon-based organometallic compound, the substrate under near atmospheric pressure, SiO ₂ thin film forming method using a discharge plasma, characterized in that the plasma discharge About.

[0002]

2. Description of the Related Art Conventionally, a method of forming a thin film using plasma generated by glow discharge under low pressure conditions has been put to practical use, but processing under low pressure conditions requires a vacuum vessel or a vacuum apparatus. However, every time the processing is performed in a batch, it is necessary to break the vacuum of the vacuum container and perform a new evacuation, which is industrially very disadvantageous. Therefore, it has been applied only to expensive articles such as electronic parts.

In order to solve the above problems, various methods have been proposed for generating discharge plasma under a pressure near the atmospheric pressure. For example, Japanese Patent Publication No. 2-48626 discloses a method of performing treatment using plasma generated in a mixed atmosphere of helium and ketone near atmospheric pressure, and Japanese Patent Application Laid-Open No. 4-74525. Discloses a method of performing treatment using plasma generated in an atmosphere near the atmospheric pressure composed of argon and helium or acetone.

However, each of the above methods is a method of generating plasma in a gas atmosphere containing helium or ketone. Not only is the gas atmosphere limited, but when helium is used, helium itself is expensive. Since it is industrially disadvantageous and can only achieve a discharge state with a low electron density, it is used only for limited surface treatment, and it has not been possible to form an inorganic thin film.

On the other hand, in the formation of a SiO ₂ thin film using discharge plasma (hereinafter sometimes referred to as “thin film formation”), in order to avoid the occurrence of arc discharge due to dielectric breakdown of the conventional discharge plasma, a lower voltage and a lower voltage are required. A SiO ₂ thin film has been formed at a high concentration of 1% by volume or more of a silicon organometallic compound in a gas atmosphere.

[0006]

However, according to the study of the present inventors, since silicon-based organometallic compounds are relatively stable, their reaction efficiency is poor in low-voltage plasma discharge,
Further, there is a problem that the film quality and the film thickness change over time within one week immediately after the film formation. In particular, as for the film thickness, the degree of film thickness reduction ((film thickness after aging) / initial film thickness) × 10
0%) was about 70%, which proved that there was a problem that the film thickness control to the set film thickness was extremely difficult, a curing step after film formation was essential, and the productivity was poor. In order to solve these problems, the present inventors have developed a method for forming a metal-containing thin film by generating discharge plasma by applying an electric field in a gas atmosphere containing a metal compound under a pressure near atmospheric pressure. And studied further. (Japanese Patent Application No. 10
However, in the case of a silicon-based organometallic compound, the reactivity is low. Therefore, even if a film is formed using this method, it is not possible to sufficiently suppress the temporal change of the film quality and the film thickness immediately after the film formation. could not. Therefore, the present invention has been made in order to solve the above-mentioned problems that the present inventors have found about a method of forming a SiO ₂ thin film using discharge plasma, and it is intended that the thickness and film quality of the formed SiO ₂ thin film be improved. It is an object of the present invention to provide a method for forming a thin film in which a change with time is suppressed.

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In addition, the present invention according to claim 1 provides a system under a pressure near atmospheric pressure.
In a gas atmosphere containing a recon-based organometallic compound,
Discharge current density between poles is 0.01 to 300 mA / cm^TwoWhen
By applying an electric field so that
Generate and form a silicon-based organometallic compound-containing thin film
When the silicon-based organometallic compound concentration in the above gas atmosphere is
Degree is 0.01 to 0.2% by volume, and the electric field strength is 65 to 1
Discharge plasma characterized by being 50 kV / cm.
SiO used_TwoProvided is a method for forming a thin film. Also, billing
Item 2 The present invention described in Item 2 relates to a silicon-based organometallic compound.
2. The method according to claim 1, wherein lamethoxysilane is used.
SiO using discharge plasma _TwoSuggest thin film formation method
Offer. The present invention described in claim 3 provides the above-mentioned pair of pairs.
It is characterized by applying a pulsed electric field between the facing electrodes
The Si using the discharge plasma according to claim 1 or 2.
O_TwoProvided is a method for forming a thin film. . Further, according to claim 4
The present invention provides a method for applying a voltage in the application of the above-described pulsed electric field.
Rise or fall time is 40 ns to 100 μm
s and the intensity of the pulsed electric field is 65 to 150 k.
V / cm range.
SiO using the discharge plasma according to any one of the above._Two
Provided is a method for forming a thin film. The present invention according to claim 5.
Means that the frequency of the pulsed electric field is 1 to 100 kHz.
z, and the formation time of one pulsed electric field is 1
5 to 1000 μs.
SiO using the discharge plasma according to any one of the above._Two
Provided is a method for forming a thin film. Hereinafter, the present invention will be described in detail.

In the present invention, the pressure near the atmospheric pressure is 1
A pressure of 00 to 800 Torr, in particular, 700 to 780 Torr which facilitates pressure adjustment and facilitates device configuration.
It is preferable to set the pressure range.

The discharge current density between the electrodes in the present invention refers to a value obtained by dividing the value of the current flowing between the electrodes due to discharge by the area of the discharge space in the direction orthogonal to the current flow direction. If you use
It corresponds to a value obtained by dividing the current value by the facing area. or,
When a pulsed electric field is formed between the electrodes, a pulsed current flows. In this case, the pulse current refers to the maximum value of the pulse current, that is, a value obtained by dividing the peak-to-peak value by the area.

Generally, the electron density in a plasma, that is, the plasma density, is measured by a probe method or an electromagnetic wave method. However, at pressures near atmospheric pressure, the discharge between the electrodes is
Originally, it is easy to shift to arc discharge. Therefore, in the probe method in which the probe is inserted into the plasma, an arc current flows through the probe, and accurate measurement cannot be performed. In addition, the electromagnetic wave method based on emission spectroscopy or laser absorption analysis is difficult to analyze because the information obtained differs depending on the type of gas.

On the other hand, in a glow discharge at a pressure close to the atmospheric pressure, the gas molecule density is higher than that in a low gas pressure discharge, so that the life after ionization and recombination is short, and the mean free path of electrons is also small. short. Therefore, there is a feature that the glow discharge space is limited to the space between the electrodes. Therefore, the electrons in the plasma are directly converted into a current value through the electrode, and the electron density (plasma density) is considered to be a value reflecting the discharge current density. It has been found that thin film formation control is possible. As described above, in the glow discharge under a pressure near the atmospheric pressure, the discharge current density reflects the plasma density for the above-described reason.

Therefore, the discharge current density between the electrodes is preferably in the range of 0.01 to 300 mA / cm ² under the pressure near the atmospheric pressure of the gas atmosphere containing the silicon-based organometallic compound. By setting the discharge current density to the above, the silicon-based organometallic compound is plasma-excited, and the plasma is maintained in a glow discharge state.
It becomes possible to form an O ₂ thin film.

In the present invention, when the discharge current density is in the range of 0.01 to 300 mA / cm ² , the electric field intensity is 65 to 150 kV when applied to the electrode.
/ Cm is preferable. If it is less than 65 kV / cm, it takes too much time to process, and 150 kV / cm
This is because an arc discharge is generated when the ratio exceeds.

In the present invention, in order to relatively easily realize a discharge current density between the electrodes of 0.01 to 300 mA / cm 2, a pulsed electric field is applied between the opposed electrodes. Methods can be mentioned. In a method of applying a normal AC electric field, under a pressure close to the atmospheric pressure, a glow discharge state is not stably maintained in a gas other than a specific gas such as helium, ketone, etc. And it is difficult to maintain a plasma of a metal compound such that a metal element-containing thin film is formed.

In the present invention, the electric field applied between the opposed electrodes used for generating plasma is preferably a pulsed electric field. At a pressure close to the atmospheric pressure, except for a gas component that takes a long time to transition from the above-described plasma discharge state to the arc discharge state, the plasma discharge state is not stably maintained, but instantaneously transitions to the arc discharge state, so that it is pulsed. By applying an electric field, it is considered that a cycle in which the discharge is stopped before the transition to the arc discharge and the discharge is started again is realized, and the discharge plasma is stably maintained even in an atmosphere other than the above specific gas. This is because it is possible to generate

By using a pulsed electric field, it is possible to generate a discharge plasma in the air, so that an open system can be used.

FIG. 1 shows an example of a pulse voltage waveform. The waveforms (a) and (b) are impulse waveforms, the waveform (c) is a pulse waveform, and the waveform (d) is a modulation waveform. Although FIG. 1 shows an example in which voltage application is repeated positive and negative, a pulse of a type in which a voltage is applied to either the positive or negative polarity side may be used. FIG. 2 shows a block diagram of a power supply when such a pulse voltage is applied.

The pulse voltage waveform is not limited to the above-mentioned waveforms, but the shorter the rise time of the pulse, the more efficiently the gas is ionized during the generation of plasma. Since the rise time is determined by the power supply to be used, a power supply having a rise time as short as possible is selected.

Further, modulation may be performed using pulses having different pulse waveforms, rise times, and frequencies. Such modulation is effective in performing high-speed continuous surface treatment.
Also, a higher pulse frequency and a shorter pulse width are suitable for high-speed continuous surface treatment.

In the present invention, as for the pulse voltage applied between the electrodes, the shorter the rise time and the fall time of the pulse, the more efficiently the gas is ionized during the generation of plasma. In particular, the rise and fall times of the pulse voltage applied between the electrodes, in other words, the rise and fall times of the pulse electric field formed between the electrodes,
In each case, it is preferable to set it to 40 ns to 100 μs.
Less than 40 ns is not realistic, and if it exceeds 100 μs,
The discharge state easily shifts to arc discharge and becomes unstable.

Here, the rise time refers to the time during which the direction of the voltage change is continuously positive, and the fall time refers to the time during which the direction of the voltage change is continuously negative. I do.

Further, the magnitude of the electric field strength is such that the rise and fall times of the pulse electric field are 40 ns to 100 ns.
In the range of μs, the electric field strength is 65 to 65 when applied to the electrode.
The range is preferably 150 kV / cm. 6
If the pressure is less than 5 kV / cm, it takes too much time for the treatment.
This is because if it exceeds 50 kV / cm, arc discharge occurs. In applying the voltage, a direct current may be superimposed.

The pulse electric field formed between the electrodes may have its pulse waveform, rise and fall times, and frequency appropriately modulated. The pulse electric field having a higher frequency and a shorter pulse width is more suitable for forming a high-speed continuous thin film.

In the present invention, the frequency of the pulse electric field applied between the electrodes is preferably in the range of 1 kHz to 100 kHz. If it is less than 1 kHz, the thin film forming speed is too slow to be realistic, and if it exceeds 100 kHz, arc discharge is likely to occur.

The formation time of one pulse electric field is 1 μm.
It is preferably from s to 1000 μs, more preferably from 3 to 200 μs. If it is less than 1 μs, the discharge becomes unstable, and if it exceeds 1000 μs, it is easy to shift to arc discharge. Here, the formation time of one pulse electric field refers to the continuous duration of one pulse waveform in a pulse electric field where ON / OFF is repeated, in other words, the pulse duty time, as illustrated in FIG.

In the present invention, there is no space in the plasma generation space.
Raw material gas out of existing gases (hereinafter referred to as processing gas)
Are particularly limited as silicon-based organometallic compounds.
For example, tetramethoxysilane; Si (OC
H_Three)_Four, Tetraethoxysilane; Si (OC_TwoH_Five)
_Four, Methyltriethoxysilane; (SiCH_Three(OCH
_Three)_Three, Tetramethylsilane; Si (CH_Three)_Four, Tet
Laethylsilane; Si (C _TwoH_Five)_FourAnd the like.
More preferably, tetramethoxysilane and the like are mentioned.
By using these relatively reactive,
Further, a change with time can be suppressed.

The concentration of the silicon-based organometallic compound in the processing gas is preferably 0.01 to 0.2% by volume. When the concentration is less than 0.01% by volume, when the electric field strength is 65 kV / cm or more, the reaction efficiency is high, and the powder reacts in the gas phase, and when the electric field strength is 65 kV / cm or less, the film formation rate is very slow. If the concentration is higher than 0.2% by volume, the film thickness and film quality after film formation change with time. Further, even when the concentration is in the range of 0.01 to 0.2% by volume,
When the electric field intensity is smaller than 65 kV / cm, a change with time after film formation occurs, and when the electric field intensity is 150 kV or more, powdering occurs.

In order to introduce the silicon-based organometallic compound into the discharge space, it may be in a gas, liquid or solid state at normal temperature and normal pressure. In the case of a gas, it can be introduced into the discharge space as it is, but in the case of a liquid or solid, it is used after being vaporized by means such as heating or decompression. When the silicon-based organometallic compound is used after being vaporized by heating, it is preferably a liquid such as tetraethoxysilane which is liquid at normal temperature and has a boiling point of 200 ° C. or less. It may be used after being diluted with a solvent, and the solvent may be methanol, ethanol, n
-An organic solvent such as hexane and a mixed solvent thereof may be used. The above-mentioned diluting solvent is decomposed into a molecular state and an atomic state in the glow discharge, so that the influence on the formed thin film can be ignored.

Further, a gas such as oxygen may be mixed as a reaction gas in the processing gas. By using a reaction gas, a dense metal oxide thin film having a small amount of organic components can be formed, and the deposition rate can be improved. In particular, when oxygen gas is used, it is considered that the oxidizing action of the oxygen gas has an effect of promoting the conversion of stable silica-based alkoxide into SiO ₂ .

When the above reaction gas is used, the concentration in the processing gas is preferably in the range of 0 to 99.99% by volume. More preferably, the content is 10 to 20% by volume.

From the viewpoint of economy and safety, it is preferable to use a diluent gas such as a rare gas or an inert gas in the above-mentioned processing gas. Examples of the diluent gas include rare gases such as helium, neon, argon, and xenon, and nitrogen gas. These may be used alone or in combination of two or more. The concentration of the diluent gas in the processing gas is
It is preferable to use in the range of 0 to 99.99% by volume. More preferably, it is 80 to 90% by volume.

As a processing gas, a compound having more electrons is more advantageous in increasing the plasma density and performing high-speed processing.

Further, in order to obtain high-density plasma, it is effective to decompose gas in the presence of a compound having many electrons (compound having a large molecular weight), which is used for forming a thin film on a substrate. The present invention can also be applied to an inert gas used as a diluent for a reaction gas. Therefore, the inert gas used in the present invention preferably has a molecular weight of 10 or more.
When a gas such as helium having a molecular weight of less than 10 is used as a diluent, even if glow discharge continues, only a discharge state with a low electron density can be achieved, and a thin film is not formed or formed. The speed is too slow, resulting in uneconomic consequences.

The method for forming a thin film of the present invention performed in a gas atmosphere containing nitrogen and oxygen does not need to keep the line of the apparatus confidential in order to eliminate the incorporation of air.
Rather, the air can be actively used, which has a great industrial advantage.

The processing gas of the present invention comprises the above-mentioned raw material gas,
It is preferable that three types of gases, a reaction gas and a dilution gas, are combined and mixed, and introduced between the electrodes of the plasma generator at a temperature at which the raw material gas does not liquefy.

In the method for forming a thin film of the present invention,
As the gas existing in the discharge plasma generation space, a known arbitrary processing gas may be used in addition to the silicon-based organometallic compound to form a composite film.

In the method of the present invention, the object to be formed into a thin film is not particularly limited. Examples of the material of the substrate include polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, and polytetrafluoroethylene. , Plastic such as acrylic resin, glass, ceramic, metal and the like. In addition, as the shape of the substrate, plate-like, film-like,
Sheet-like materials, further, woven fabrics, non-woven fabrics, yarns, strings, and the like can be mentioned, but are not particularly limited thereto. According to the thin film forming method of the present invention, on a surface of a base material of various shapes. A thin film can be easily formed.

The plasma generator used for forming the thin film of the present invention may be of a batch type or of a type capable of continuous processing, as long as the plasma processing conditions can be achieved.

In the apparatus used in the present invention, the counter electrode is usually accommodated in a container, and the inside of the container is filled with an atmospheric gas. The material of the container is not particularly limited, and a resin, glass, or the like is preferably used. If the container has a structure in which the electrodes are insulated from the electrodes, metals such as stainless steel and aluminum can also be used. .

In the method of the present invention, the substrate on which the thin film is to be formed may be heated or cooled, but can be sufficiently processed at room temperature.

In the method of forming a thin film according to the present invention, the material of the electrode used may be a simple metal such as copper or aluminum,
Examples thereof include alloys such as stainless steel and brass, and intermetallic compounds.

Further, in order to avoid the occurrence of arc discharge due to electric field concentration, it is preferable that the electrodes have a structure in which the distance between the electrodes is substantially constant. Examples thereof include an opposed flat plate type, a spherical opposed flat plate type, a hyperboloid opposed flat plate type, and a coaxial cylindrical type structure.

In the present invention, it is preferable to provide a solid dielectric on one or both of the opposing surfaces of the electrodes. In addition, if there is a portion where the electrodes directly face each other without being covered by the fixed dielectric, an arc discharge is likely to occur therefrom, so that the solid dielectric is in close contact with the electrode on which the solid dielectric is placed, and the electrode in contact with the electrode Is completely covered.

The solid dielectric may be in the form of a sheet or a film, but preferably has a thickness of about 0.5 to 5 mm. If the thickness is too large, a high voltage is required to generate discharge plasma. If it is too thin, dielectric breakdown occurs when voltage is applied, and arc discharge occurs.

The material of the solid dielectric is plastic such as polytetrafluoroethylene or polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide and titanium dioxide, and double oxides such as barium titanate. Is mentioned.

However, the solid dielectric has a relative dielectric constant of 2
It is preferable that the above conditions are satisfied (in a 25 ° C. environment, the same applies hereinafter).
Examples of such a dielectric include polytetrafluoroethylene, glass, and a metal oxide film. or,
In order to stably generate discharge plasma having a discharge current density of 0.01 to 300 mA, it is advantageous to use a fixed dielectric having a relative dielectric constant of 10 or more. The upper limit of the relative permittivity is not particularly limited, but is 18, 18 in actual materials.
About 500 are known. The solid dielectric having a relative dielectric constant of 10 or more includes a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide film containing zirconium oxide. The thickness of the coating is 10 to 1000
It is preferable to use one having a size of μm.

In the present invention, the distance between the pair of electrodes is determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using plasma, and the like, and is preferably 1 to 50 mm. If it is less than 1 mm, it is insufficient to provide a space for disposing the base material when plasma generated during the process is used for surface treatment or the like, and if it exceeds 50 mm, it becomes difficult to generate uniform discharge plasma. .

Hereinafter, a continuous discharge plasma generator using a roll electrode (hereinafter, referred to as a roll electrode device) used by the present inventors will be described.

The above-mentioned roll-shaped electrode device is composed of a roll-shaped electrode and a curved electrode having a curved surface facing the roll-shaped electrode at substantially equal intervals, and a discharge space is formed between the two facing surfaces. One of the electrodes is a discharge surface provided with a solid dielectric.

Hereinafter, the apparatus used in the present invention will be described in detail with reference to the drawings. FIG. 3 is a partially enlarged schematic sectional view showing an example of a discharge plasma processing apparatus suitably used in the present invention. As shown in FIG. 3, a substantially cylindrical roll electrode 1 and a curved electrode 2 are opposed at substantially equal intervals, and a discharge space 3 is formed between the opposed surfaces of the roll electrode 1 and the curved electrode 2. ing. Both electrodes are provided with a solid dielectric, and the outermost facing surface of the discharge space 3 is called between the discharge surfaces 11 and 21.

The roll electrode 1 is grounded.
A pulse electric field is applied between the roll electrode 1 and the curved electrode 2 from the pulse voltage application power source 22 shown in FIG.

On the other hand, the base material 4 is supplied from the unwinding roll 80, comes into close contact with the discharge surface 11 of the roll electrode 1, and is taken up by the take-up roll 81. The roll electrode 1 is rotatable, and the rotation speed is the same as the transport speed of the substrate 4. Since the portion of the substrate 4 that is in contact with the discharge plasma generated in the discharge space 3 is processed, only the upper surface of the substrate 4 is processed.

The container 5 includes a gas introduction container 6 and a gas discharge container 7. The processing gas is supplied from the gas cylinder 61 to the discharge space 3 via the gas introduction container 6,
After processing, the gas is exhausted from the gas exhaust container 7. Therefore, by appropriately selecting the processing gas, the surface of the substrate 4 is processed, and the surface-treated product 41 is obtained.

FIG. 4 is a cross-sectional view of the vicinity of FIG. As shown in FIG. 4, the discharge surface 21 of the curved electrode 2 has a smooth continuous curved surface 25 extending from the substrate carrying-in portion 63 to the side surface 23, thereby preventing occurrence of arc discharge in this region. In addition,
Although not shown, the other end is similarly formed into a smooth and continuous curved surface, and the side surface of the discharge space 3 is sealed with a hard-coated polyethylene terephthalate film (not shown) in the direction of rotation of the roll-shaped electrode 1. Have been.

Further, as shown in FIG.
The gap is made smaller than the distance between the respective discharge surfaces 11 and 21 of the roll electrode 1 and the curved electrode 2. At the end of the substrate carrying-in portion 63, a gas introduction port 62 communicating with the gas introduction container 6 (not shown) is provided on the curved electrode 2 side so that a processing gas can be supplied into the discharge space 3. Therefore, in this case, the processing gas introduced from the gas inlet 62 can prevent the backflow from the discharge space 3 to a minimum.

Further, as described above, since the roll electrode 1 is rotated at the same speed as the transport speed of the base material 4, the processing gas also moves along with the rotation of the roll electrode 1. It can be supplied sufficiently even at low pressure. In addition, the curved surface 2 is also formed at the end of the base material discharge side (gas discharge container 7 side).
The structure is symmetrical to 5.

It is preferable that the processing gas is uniformly supplied to the plasma generation space. When processing in a mixed gas of a processing gas and an inert gas, since the inert gas is lighter than the processing gas, a device must be devised to avoid non-uniformity during supply. In particular, when treating a substrate having a large area, care must be taken since the substrate tends to be uneven. FIG. 5 shows a preferred embodiment of the gas supply container 6 and the gas exhaust container 7 in the example shown in the apparatus of FIG.

FIGS. 5A and 5B show an example of a gas introduction container suitably used in the above-mentioned apparatus, in which FIG. 5A is a sectional view, FIG. 5B is a view taken in the direction of arrow B, and FIG. is there. A gas supply port 64 to which a gas pipe G from a gas cylinder 61 (see FIG. 3) is connected is provided at one longitudinal end of the rectangular gas introduction container 6, and the gas introduction container is opposed to the gas supply direction. By providing the swash plate 65 on the diagonal line of FIG. 6, a section is formed that becomes narrower as the distance from the gas supply port 64 increases, and the reaction gas introduced from the gas supply port 64 is turbulent, and the density in the section is substantially reduced. At the same time, the flow speed is made substantially uniform and the direction is deflected. Then, the gas flow is introduced into the gas introduction port 62 composed of a number of uniform small holes provided near the edge of the gas introduction container 6. (Communication) to rectify and blow out the gas.

The gas introduction container 6 is provided in Japanese Patent Application No.
As shown in Japanese Patent No. 85520, a two-chamber structure may be adopted.

[0060]

EXAMPLES In order to explain the thin film forming method of the present invention in more detail, examples and comparative examples are described below.

Example 1 The roll electrode 1 of the apparatus of the present invention shown in FIG. 3 (a 1 mm thick solid dielectric 11 composed of 20% by weight of TiO2 and 80% by weight of Al2 O3) was coated by thermal spraying: diameter 400mm, length 1080
5) on a curved electrode 2 (a radius of curvature of 202 mm, a diameter of 100 mm, a length of 810 mm, and a solid dielectric 21 equivalent to the solid dielectric 11 are formed) facing each other at an interval of 2 mm. Gas inlet (length 810 mm, width 100 mm, height 60 mm) 62 from the introduction container 6
In a container 5 provided with a substrate, a substrate carrying-in portion 63 (interval of 0.5 mm between the curved surfaces 25 on the side surfaces 23 of the roll electrode 1 and the curved electrode 2) is used. 1 was placed in close contact with the discharge surface 11.

Further, the inside of the container 5 is evacuated to 10 Torr by a vacuum pump, and then, through a gas inlet muff controller, 34 SLM of argon and 8 S of nitrogen as processing gases.
A mixed gas of LM, 8 SLM of oxygen, and 0.2 cc / min (0.04% by volume) of methyltriethoxysilane (hereinafter referred to as MTEOS) was introduced until 760 Torr.

Next, the unwinding roll 80 and the take-up roll 81
While applying a tension of 10 kgf / m ^{2 in} between, the base material 4 is conveyed at a traveling speed of 0.5 m / min.
The roll electrode 1 was rotated in the same direction. The flow rate at this time was 50 SLM.

Next, after the roll electrode 1 and the curved electrode 2 were heated to 60 ° C. with circulating water, a discharge voltage of 17 kV (electric field intensity) was applied between the roll electrode 1 and the curved electrode 2 by a pulse power source having a rising speed of 5 μsec. Plasma was generated between the electrodes at 85 kV / cm, a discharge current density of 0.03 mA / cm ² ) and a frequency of 4 kHz, and a thin film of SiO ₂ was continuously formed on the surface of the polyethylene terephthalate substrate. A uniform thin film was formed on the obtained surface-treated product, and no defects or wrinkles were confirmed. <Measurement of change over time> The film on which the SiO ₂ thin film was formed was allowed to stand at 60 ° C. and 95% RH for 150 hours according to the method described above, and changes in the film thickness and the refractive index of the film were measured. The results are shown in Table 1. Degree of decrease in film thickness ((film thickness after aging / initial film thickness) × 100
%) The refractive index and the film thickness were measured using an ellipsometer (Model “BVA-36VW”, manufactured by Mizojiri Optical Industrial Co., Ltd.).

[0065]

[Table 1]

(Example 2) As a processing gas, a mixed gas of 34 SLM of argon, 8 SLM of nitrogen, 8 SLM of oxygen, and 0.75 cc / min (0.15% by volume) of tetramethoxysilane (hereinafter referred to as TMOS) was introduced. , Discharge voltage 13
kV (electric field strength 65 kV / cm, discharge current density 0.04
A thin film of SiO ₂ was continuously formed on the film by performing the same process as in Example 1 except that the current was ² mA / cm ² ). Table 1 shows the changes over time in the film thickness and the refractive index of the film.

(Embodiment 3) As processing gases, argon 34 SLM, nitrogen 8 SLM, oxygen 8 SLM, TMOS
Same as Example 1 except that a mixed gas of 0.3 cc / min (0.06% by volume) was introduced and discharge voltage was set to 17 kV (electric field intensity: 85 kV / cm, discharge current density: 0.03 mA / cm ² ). By performing various treatments, a thin film of SiO ₂ was continuously formed on the film. Table 1 shows the changes over time in the film thickness and the refractive index of the film.

(Comparative Example 1) As processing gases, argon 34 SLM, nitrogen 8 SLM, oxygen 8 SLM, MTEOS
Same as Example 1 except that a mixed gas of 1.5 cc / min (0.3% by volume) was introduced, and the discharge voltage was set to 10 kV (electric field intensity 50 kV / cm, discharge current density 0.05 mA / cm ² ). By performing various treatments, a thin film of SiO ₂ was continuously formed on the film. Table 1 shows the changes over time in the film thickness and the refractive index of the film.

[0069]

According to the method of forming a thin film of the present invention as described above, the formation of an inorganic thin film, which has been conventionally performed under low pressure, can be performed even near atmospheric pressure. Further, by setting the processing conditions as described above, a thin film containing a silicon-based organometallic compound can be formed in a short time and continuously. In addition, since the change with time in the film thickness and film quality after film formation can be suppressed, the film thickness can be easily controlled, and the productivity can be improved because a curing step is not required.

[0070]

[Brief description of the drawings]

FIG. 1 is a voltage waveform diagram showing an example of a pulsed electric field.

FIG. 2 is a block diagram of a power supply that generates a pulsed electric field.

FIG. 3 is a partially enlarged schematic cross-sectional view showing an example of a preferred discharge plasma processing apparatus used in the present invention.

FIG. 4 is a cross-sectional view of the vicinity of A in FIG. 3 showing a portion for carrying a substrate into a discharge surface of a curved electrode suitably used in the present invention.

FIG. 5 shows an example of a gas introduction container in a plasma processing apparatus suitably used in the present invention, and FIG.
(B) is a view on arrow B, and (c) is a cross-sectional view of the same CC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roll electrode 2 Curved electrode 11, 21 Discharge surface (solid dielectric) 23 Side surface of curved electrode 25 Continuous curved surface 3 Discharge space 4 Base material 5 Container 62 Gas inlet 63 Substrate carry-in part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F073 AA28 BA07 BA08 BA16 BA18 BA19 BA24 BA26 BB01 BB04 CA01 CA70 HA09 HA12 HA15 4K030 AA06 AA09 AA14 AA16 AA18 BA44 FA03 GA02 GA14 JA06 JA09 JA11 JA14 JA18

Claims (5)

[Claims] An electric field is applied between opposite electrodes under a pressure near the atmospheric pressure in a gas atmosphere containing a silicon-based organometallic compound so that a discharge current density is 0.01 to 300 mA / cm ^2. When a discharge plasma is generated to form a silicon-containing organometallic compound-containing thin film, the concentration of the silicon-containing organometallic compound in the gas atmosphere is 0.01 to
0.2 vol%, the electric field strength is 65 to 150 kV / cm
SiO using discharge plasma characterized by the following:
₂ Thin film formation method. 2. A SiO ₂ thin film forming method using a discharge plasma according to claim 1, characterized by using a tetramethoxysilane silicon-based organometallic compounds. 3. A SiO ₂ thin film forming method discharge plasma use according to claim 1 or 2, characterized in that applying a pulsed electric field between the pair of opposed electrodes. 4. A voltage rising or falling time in the application of the pulsed electric field is 40 ns to 10 ns.
0 μs, and the intensity of the pulse electric field is 65 to 15
The pressure is in the range of 0 kV / cm.
3. Si using the discharge plasma according to any one of 3.
O ₂ thin film forming method. 5. The pulsed electric field has a frequency of 1 to 5.
Is 100kHz, and, SiO ₂ thin film forming method using a discharge plasma according to claim 1 in which formation time of the one pulse electric field is characterized by a 1～1000Myuesu.