JP2003013238A - Apparatus and method for forming deposited film with plasma cvd method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for forming a deposited film with a plasma CVD method, which improves uniformity of a deposited film quality, consequently improves product quality, and reduces a manufacturing cost by increasing a non-defective rate. SOLUTION: This apparatus for forming the deposited film with the plasma CVD method comprises a reaction vessel 140 capable of producing a hermetical vacuum, which is connected with an exhaust means, a gas introduction means 112 for introducing a source gas into the reaction vessel 140, a means 103 for introducing high-frequency electric power into the reaction vessel, introducing the source gas into the reaction vessel 140, applying the high-frequency electric power, and forming the deposited film on the substrate arranged in the reaction vessel, by using the plasma generated in a discharge space in the reaction vessel. The apparatus has a plasma sealing body 113 between an outlet and the discharge space. The plasma sealing body 113 has at least in a part, a region provided with several openings of such a size as to pass no plasma, of which the surface area is larger than the area of the opening of the outlet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deposited film forming apparatus by a plasma CVD method for forming an amorphous semiconductor to be a deposited film on a substrate, and more particularly to a semiconductor device, a photoreceptive member for electrophotography, a line sensor for image input, and imaging. Plasma CV used for devices, photovoltaic devices, etc.
The present invention relates to a deposited film forming apparatus and a deposited film forming method for forming an amorphous semiconductor to be a functional deposited film by the D method.

[0002]

2. Description of the Related Art Conventionally, as element members used for semiconductor devices, electrophotographic photoconductors, image input line sensors, image pickup devices, photovoltaic devices, various other electronic elements, optical elements, etc., for example, hydrogen or /
And the use of non-single crystalline deposited films of amorphous silicon, such as amorphous silicon compensated with halogen (eg fluorine, chlorine, etc.) or crystalline deposited films such as diamond thin films, among which Some have been put to practical use.

Then, such a deposited film is a plasma CV.
Method D, that is, a method of decomposing a source gas by glow discharge by direct current or high frequency, or microwave to form a deposited film on a support such as glass, quartz, heat-resistant synthetic resin film, stainless steel, and aluminum. Various devices have been proposed for that purpose. For example, Japanese Patent Application Laid-Open No. 8-339963 discloses that the wall of the chamber is made of a dielectric and most of it is made of a window, and the electrodes are arranged outside instead of being arranged in a vacuum container, thereby improving the film quality and production. It is possible to improve the sex.

Further, for example, Japanese Patent Laid-Open No. 10-068082.
The publication discloses that a plurality of rod-shaped electrodes are coupled with a dielectric and electric power is supplied to each of the electrodes to achieve further homogenization.

[0005]

With the above-described apparatus and method, it has become possible to form a good deposited film. However, the market demand level for products using such a deposited film forming apparatus is increasing day by day, and in order to meet this requirement, a deposited film forming apparatus capable of producing higher quality products at low cost is required. ing.

In digital electrophotographic apparatuses and color electrophotographic apparatuses, which have been remarkably popularized in recent years, not only text originals but also photographs, pictures, design images and the like are frequently copied. Therefore, for example, a plasma CVD apparatus is used. In the case of forming an electrophotographic photoreceptor, the level of demand for reducing unevenness in the density of copy images is extremely high, and there is an urgent need to provide an electrophotographic apparatus that can meet this demand.
Among them, it is an unavoidable problem to improve the uniformity of the characteristics of the electrophotographic photoreceptor, and in order to solve the problem, it is necessary to provide a deposited film forming apparatus and a deposited film forming method capable of improving the uniformity of the deposited film. Development is strongly demanded.

A deposited film forming apparatus capable of improving the uniformity of a deposited film is strongly required not only for improving product quality but also for reducing production cost. This is because, for example, when a deposited film is formed on many substrates in one furnace in order to improve productivity, the characteristics of each substrate may differ even within the same lot due to the non-uniformity of the deposited film. This is because, as a result, a product in which the required level of characteristics cannot be obtained may be produced, and as a result, the non-defective product rate at the time of production may be reduced.

Therefore, the present invention solves the above problems and improves the uniformity of the film quality of the deposited film, thereby improving the product quality and at the same time, it is possible to achieve a reduction in production cost by improving the yield rate. An object is to provide a deposited film forming apparatus and a deposited film forming method.

[0009]

In the deposited film forming apparatus by the plasma CVD method of the present invention which achieves the above-mentioned object, a raw material gas is reacted with a vacuum-tight reaction container having an exhaust port connected to an exhaust unit. It is equipped with a gas introduction means for introducing into the reaction vessel and a means for introducing high-frequency power into the reaction vessel, introduces a raw material gas into the reaction vessel and applies high-frequency power, and it is generated in the discharge space in the reaction vessel. A deposited film is formed on the substrate arranged in the reaction container by using the plasma thus generated. Further, a plasma leak preventer is provided between the exhaust port and the discharge space, and the plasma leak preventer has a region in which at least a part of the plasma leak preventer is provided with a plurality of openings of a size that does not allow plasma to pass therethrough. And the surface area of the region is larger than the area of the opening of the exhaust port.

The region of the plasma leakage preventer provided with the plurality of openings is made of punching metal, and the size of each hole of the punching metal is 0.8 mm ² or more 8
And a 0 mm ² or less, the punching metal of aperture ratio may be 80% or less than 20%, is composed of a metal mesh, eye number of vertical lines in the 25.4mm one side of the metal mesh is 2.5 The wire diameter of the metal mesh may be 0.14 mm or more and 5 mm or less.

Further, the plasma leak preventer has a cylindrical portion and a flat surface portion arranged on an end face of the cylindrical portion, and at least a part of the cylindrical portion has a plurality of openings of a size that does not allow plasma to pass therethrough. It may be provided, and the insulator may be arranged on at least a part of the plane portion. This is more effective because it is possible to reduce film peeling from the plasma leak preventer, which may adversely affect the deposited film formed by disposing the insulator.

Further, the plasma leak preventer may be provided with a dome portion, and at least a part of the dome portion may be provided with a plurality of openings of a size that does not allow plasma to pass therethrough.

In forming a deposited film by the plasma CVD method of the present invention, the inside of a reaction vessel that can be vacuum-tight is exhausted by an exhaust means, a source gas is introduced into the reaction vessel, and high-frequency power is applied from the high-frequency power introduction means. By using the plasma generated as a result, a deposited film is formed on the substrate arranged in the reaction container. There, the exhaust by the exhaust means is performed via a plasma leak preventer provided between the exhaust port of the reaction vessel and the discharge space, and as the plasma leak preventer, at least part of the plasma does not pass. The plasma leak preventer has a region in which a plurality of openings having a size are provided, and the surface area of the region is larger than the area of the opening of the exhaust port of the reaction container.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention achieves the above-mentioned object of the present invention by the above-mentioned constitution.
It is based on the following findings of the present inventors.

In order to further homogenize the characteristics of the deposited film, one method is to increase the applied power power. In particular, when a deposited film is formed on many substrates in one furnace in order to reduce the cost, the effect is high. However, in that case, plasma easily leaks from the discharge space to the exhaust pipe, and the discharge leakage may cause variations in characteristics. Further, the plasma leakage causes film deposition at the point where the plasma leaks, and the deposited film peels off to become a source of spots.

The leakage of the discharge can be prevented, for example, by providing a mesh plate between the discharge space and the exhaust pipe and reducing the opening area of the opening provided in the mesh plate. In this case, the conductance becomes low, and when adjusting the discharge space to a certain degree of vacuum, the range of the degree of vacuum that can be reached is narrowed. In some cases, it becomes difficult to form a deposited film at a preferable degree of vacuum, It is necessary to devise the layout of the road.

In the case of forming a deposited film having a large area such as a photoreceptor for electrophotography, various device configurations have been proposed for making the film thickness and film quality uniform. Due to the arrangement of the members to be placed and the members to be placed around the vacuum furnace,
The degree of freedom in arranging the exhaust passage may decrease.

Further, the deposited film forming apparatus may be provided with a rotation mechanism for each substrate in order to improve the uniformity of the characteristics of the deposited film. As described above, the degree of freedom in arranging the exhaust pipe may be limited depending on the device configuration.

The inventors of the present invention have conducted intensive studies to overcome the above-mentioned problems in the conventional method for forming a deposited film and achieve the above-mentioned object of the present invention. As a result, an opening of a size that does not allow plasma to pass therethrough. The plasma leak preventer provided with a plurality of is not a flat plate-shaped one but a three-dimensional one, for example, a cup-shaped one that combines a tubular portion and a flat-shaped one, or a dome-shaped three-dimensional one. Therefore, even when forming a deposited film with high power, plasma leakage to the exhaust pipe is prevented,
We have found that a more stable deposited film can be formed. Furthermore, since sufficient conductance can be secured, the discharge space can be maintained at a desired degree of vacuum, and the range of adjustable degree of vacuum can be widened. On the other hand, it was found that the device can be adapted without making a big change to the device and the cost is excellent.

The contents of the present invention will be described in more detail below with reference to the drawings. FIG. 1A is a schematic vertical sectional view of a deposited film forming apparatus, and FIG. 1B is a cutting line AA ′ of FIG.
FIG. 3 is a schematic cross-sectional view taken along the line.

An exhaust pipe 102 is arranged in communication with the deposited film forming apparatus 101, and the other end of the exhaust pipe 102 is connected to an exhaust device (not shown). A plasma leak preventer 113 is arranged so as to cover the exhaust port through which the exhaust pipe 102 communicates with the deposited film forming apparatus 101.

A high frequency power introducing means 103 is installed in the deposited film forming apparatus 101, and the high frequency power output from the high frequency power source 105 passes through a matching box 104, and at least a part of the high frequency power introducing means 103 is made of an insulating material. It is supplied into the film formation space through the member 106 constituted by.

In the film forming space, a plurality of cylindrical substrates 107 on which deposited films are formed are arranged in a circle. Each cylindrical substrate 107 is held by a shaft 108, and the heating element 10
9 allows heating. A mechanism for rotating the shaft 108 via the gear 110 by driving the motor 111 so that the cylindrical substrate 107 rotates about its central axis in the generatrix direction is provided as necessary. 1
Reference numeral 12 is a raw material gas supply manual flow, in which a desired raw material gas is supplied into the film formation space.

At least a part of the material of the member 106 is made of an insulating material. Specific insulating materials include alumina, titanium dioxide, aluminum nitride,
Examples thereof include boron nitride, zircon, cordierite, zircon-cordierite, silicon oxide, and beryllium oxide mica-based ceramics. Of these, alumina and aluminum nitride are particularly preferable because they absorb little high-frequency power.

The deposited film is formed by using the above-mentioned apparatus, for example, as follows.

First, the reaction vessel 1 of the deposited film producing apparatus 101.
Exhaust pipe 1 in which a cylindrical substrate 107 is installed in 40, and a plasma leak preventer 113 is arranged by an exhaust device (not shown).
The reaction space of the reaction container 140 is evacuated through 02 to control to a predetermined pressure. Then, the heating element 109
Is controlled to heat the cylindrical substrate 107 to a predetermined temperature.

When the temperature of the cylindrical substrate 107 reaches a predetermined temperature, the raw material gas is introduced into the reaction space through the raw material gas supply means 112. After confirming that the flow rate of the raw material gas is the set flow rate and the pressure in the reaction space is stable, a predetermined high frequency power is supplied from the high frequency power supply 105 to the high frequency power introduction means 103 through the matching box 104. Glow discharge occurs in the reaction space by the supplied high-frequency power, and the source gas is excited and dissociated to form a deposited film on the cylindrical substrate 107.

After the desired film thickness is formed, the supply of the high frequency power is stopped, and then the supply of the raw material gas is stopped to complete the formation of the deposited film. When forming a deposited film having a multilayer structure, the same operation is repeated a plurality of times. Alternatively, the gas composition, gas flow rate, pressure,
A plurality of layers may be continuously formed by gradually changing the high frequency power to the set value of the next layer. During formation of the deposited film, the cylindrical substrate 107 may be rotated at a predetermined speed by the motor 111 via the rotating shaft 108, if necessary.

Plasma leak preventer 1 used in the present invention
In 13, the material of the member having the opening through which the gas can flow is not particularly limited, and may be an insulating material such as ceramics or a metal, but a metal that is conductive and capable of being at ground potential can reduce the thickness of the member. Therefore, it is more preferable. Further, in terms of forming processing and maintainability, a punching metal or a metal mesh is preferable, and the material is Al, Cr, Mo, Au, In,
Examples thereof include metals such as Nb, Te, V, Ti, Pt, Pd and Fe, and alloys thereof such as stainless steel.
The punching metal referred to here is a metal or alloy plate in which various patterns such as round holes and squares are punched at a constant pitch.

In the present invention, punching metal is used.
If used, the area of each hole is 0.8 mm²More than 8
0 mm²The following is desirable. The area of each hole
0.8 mm²If smaller, during deposition film formation
The film adhered to the inside of the reaction vessel 140 may be peeled off.
The dust generated by the
It becomes difficult to stably maintain the predetermined pressure inside 140.
There are cases. Therefore, the quality of the deposited film is improved and
And punching metal
Area of hole is 0.8mm²It is desirable to set the above.
The area of each hole is 80mm.²If larger, remove
It is possible to sufficiently prevent the plasma from leaking into the trachea 102.
Sometimes you can't. Therefore, the deposited film that is formed
From the perspective of improving quality and reproducibility, punching
The area of each hole in the tal is 80 mm ²Hope to be
Good

The aperture ratio of punching metal is 20%.
It is preferably 80% or less. Aperture ratio is 20%
If it is smaller, it may be difficult to maintain the pressure in the reaction container 140 at a desired value because the exhaust resistance increases. Therefore, from the viewpoint of improving the film quality and reproducibility of the deposited film formed, it is desirable that the punching metal has an aperture ratio of 20% or more. If the aperture ratio is larger than 80%, it may not be possible to sufficiently prevent plasma leakage. Therefore, the aperture ratio of the punching metal is preferably 80% or less from the viewpoint of improving the quality and reproducibility of the deposited film formed.

Further, when the metal mesh is used in the present invention, it is desirable that MESH is 2.5 or more and 60 or less. If MESH is less than 2.5, plasma leakage may not be sufficiently prevented. . Therefore, from the viewpoint of improving the film quality and reproducibility of the deposited film formed, it is desirable that MESH be 2.5 or more. Further, when the MESH exceeds 60, the mesh generated may be clogged with the dust generated by the film adhered in the reaction container 140 being peeled off during the formation of the deposited film, and the reaction container 140 is stably maintained at a predetermined pressure. Can be difficult to do. Further, since the exhaust resistance increases, it may be difficult to maintain the pressure in the reaction container 140 at a desired value. Therefore, from the viewpoint of improving the film quality and reproducibility of the deposited film formed, the metal mesh is
It is desirable to set it to SH60 or less.

The metal mesh has a wire diameter of 0.14 mm.
It is desirable that the length is 5 mm or less, and the wire diameter is 0.14.
If it is less than mm, the dust generated by peeling off the film adhering to the metal mesh during the formation of the deposited film may scatter on the surface of the substrate and cause spherical defects or the like. In addition, there may be a problem in strength, and the reproducibility of the deposited film formed may decrease. Therefore, the wire diameter of the metal mesh is preferably 0.14 mm or more. Further, if the wire diameter exceeds 5 mm, the exhaust resistance increases, and it may be difficult to maintain the pressure inside the reaction container 140 at a desired value. Therefore, the wire diameter is preferably 5 mm or less from the viewpoint of improving the film quality and reproducibility of the deposited film formed. The MESH here is the number of vertical lines on one side of 1 inch (25.4 mm).

In the present invention, the above members are
It can be used by forming it in a three-dimensional shape or by combining it. The shape of the plasma leak preventer is not particularly limited, and examples thereof include a cup-like shape having an end face and a cylindrical portion, a dome-like shape formed of a spherical surface, and a conical shape.

As a method of processing into a three-dimensional shape, it may be formed by bending such as pressing, or may be formed into a three-dimensional shape by screwing or welding.

The shape of the exhaust port on the reaction vessel side of the exhaust pipe is not limited to any shape, such as a circle, an ellipse, a rectangle or a square. The position of the exhaust port is also not particularly limited.

As the support on which the deposited film is deposited on the cylindrical substrate 107 used in the present invention, a cylindrical product is generally used, but a combination of a plurality of supports may be used. . The support may be electrically conductive or electrically insulating.

At the end of the cylindrical support, an auxiliary base may be provided at a position where the end is extended in order to make the characteristics of the support in the generatrix direction uniform.

The temperature of the support is appropriately selected in accordance with the layer design, but is usually 100 to 350 ° C.
Is desirable.

In order to make the film characteristics in the circumferential direction of the cylindrical support uniform, it is preferable to form the film while rotating the support.

In the present invention, the source gas is decomposed by applying the high frequency power to the high frequency introducing means. The frequency of the high frequency power that can be used in the present invention is not particularly limited,
Since it is easy to keep the discharge stable, 50-4
A frequency range of 50 MHz is suitable for the present invention. Any high-frequency waveform may be used, but a sine wave, a rectangular wave, or the like is suitable.

The gas pressure in the reaction vessel is appropriately selected in an optimum range, but in the usual case, it is 0.013 to 1300 Pa, preferably 0.067 to 670 Pa, and optimally 0.13 to.
It is preferably 130 Pa.

In the present invention, the control of the mixing ratio of the gas for supplying Si and the diluent gas, the temperature of the support for forming the deposited film, the gas pressure in the reaction vessel, the discharge power, the flow rate of the gas, etc. is described above. However, these conditions are not usually determined independently and separately, but based on mutual and organic relevance to form an electrophotographic photoreceptor having desired properties. It is desirable to determine the optimum value.

Similarly, it is desirable that the aperture ratio and the shape of the plasma leak preventer also take an optimum value and form based on the relationship with the above characteristic values.

[0045]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to these. (Embodiment 1) The deposited film forming apparatus shown in FIG. 1 and FIG.
Using the plasma leak preventer shown in, the diameter of the base is 8
Using a cylindrical aluminum cylinder having a length of 0 mm and a length of 358 mm, a photoreceptor having a structure of a charge injection blocking layer, a photoconductive layer and a surface layer was formed on a conductive substrate under the conditions shown in Table 1.

[0046]

[Table 1] At this time, the plasma leak preventer was changed and the photosensitive member was formed 10 times under the same conditions. As a plasma leak preventer,
Four forms were used as shown in FIG.

In the figure, the portion indicated by the mesh line is made of punching metal having a thickness of 2 mm and having openings having a diameter of 1 mm and a pitch of 4.5 mm. Further, a mounting ring 202 and a mounting hole 203 for mounting on a wall surface having an exhaust port are provided in the lower portion.

Example A is an example in which the plasma leak preventer having the cylindrical portion and the flat portion shown in FIG. 2A is used.

Example B is an example in which a plasma leak preventer having a dome-like shape shown in FIG. 2B is used.

In Example C, as shown in FIG. 2 (c), a plasma leak preventer was used in which the cylindrical part was made of punching metal as the plasma leak preventer 201 and the flat part was covered with the alumina ceramic part 204. Here is an example.

Further, Example D is shown in FIG. 2D as a comparative example.
This is an example of using a conventional planar plasma leak preventer, as shown in, to ensure conductance.
2m thickness with openings of φ3mm and pitch 4.5mm
It consisted of m punching metal.

The number of white spots and the variation in charging ability of the produced electrophotographic photosensitive member were evaluated as follows. (White spot) The light-receiving member for electrophotography is set in an electrophotographic apparatus (NP6750 made by Canon is modified for testing), and a black chart made by Canon (part number: FY9-907) is set.
The number of white spots having a diameter of 0.2 mm or less in the same area of the copy image obtained when 3) was placed on the platen and copied was evaluated.

Then, the average of 10 sets of electrophotographic light-receiving members formed into a film under the same conditions was averaged to obtain a conventional device (see FIG. 2).
Relative evaluation was performed by setting the value of the electrophotographic light-receiving member produced using (d)) to 100. (Chargeability variation) Set the electrophotographic light-receiving member in the electrophotographic device (Canon NP6750 is modified for testing), apply a current of 800 μA to the charger to perform corona charging, and use the surface electrometer for electrophotography. The dark surface potential of the light receiving member is measured. Using this value as the chargeability, measurement was performed on each of 10 sets of electrophotographic light-receiving members formed into a film under the same conditions, and the standard deviation was calculated to obtain the conventional device (FIG. 2).
Relative evaluation was performed by setting the value of the electrophotographic light-receiving member produced using (d)) to 100.

The results obtained are shown in Table 2. As is clear from Table 2, in the electrophotographic light-receiving member formed by the film forming apparatus of the present invention shown in FIGS.
It can be seen that, compared with the comparative example of (d), the variation in the occurrence of image defects called white spots is reduced, more uniform deposition film formation is possible, and the reproducibility of charging ability is improved. Further, in Example C, by covering the flat surface portion of the discharge leak preventer with alumina ceramic in a range that does not affect the exhaust of the discharge space, film peeling from the discharge leak preventer that may cause defects may occur. It was suppressed, and even better results were obtained for white spots.

As described above, by using the manufacturing apparatus of the present invention, it is possible to manufacture an electrophotographic light-receiving member having excellent image characteristics.

[0056]

[Table 2]

[0057]

As described above, according to the present invention, it is possible to further improve the uniformity of the characteristics of the deposited film in the apparatus and method for forming the deposited film on the substrate by using the plasma generated by the high frequency power. Therefore, it is possible to improve the product quality and reduce the production cost by improving the yield rate.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a deposited film forming apparatus of the present invention. (A) is a typical longitudinal cross-sectional view. (B) is (a)
3 is a schematic cross-sectional view taken along the line AA ′ in FIG.

FIG. 2 is a schematic diagram showing an example of a plasma leak preventer used in the deposited film forming apparatus of the present invention and a conventional plasma leak preventer. (A) is a perspective view of an example of the plasma leakage prevention body of the present invention. (B) is a perspective view of another example of the plasma leak preventer of the present invention. (C) is a perspective view of still another example of the plasma leak preventer of the present invention.
(D) is a perspective view of an example of the conventional plasma leak preventer.

[Explanation of symbols]

101 deposited film forming apparatus 102 exhaust pipe 103 High frequency power introduction means 104 matching box 105 high frequency power supply 106 Member composed of insulating member 107 cylindrical substrate 108 axis 109 heating element 110 gears 111 motor 112 Raw Material Gas Supply Means 113 Plasma leak preventer 140 reaction vessels 201 Plasma leak prevention unit 202 mounting ring 203 hole for mounting 204 Ceramic part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Shigeru Ueda             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H068 DA23 EA25 EA30 FA30                 4K030 BA30 FA03 JA03 KA12 KA30                       LA17                 5F045 AA08 AB04 AC01 AD06 DP25                       DP28 EG01

Claims (7)

[Claims] 1. A vacuum-tight reaction vessel having an exhaust port connected to an exhaust means, a gas introducing means for introducing a raw material gas into the reaction vessel, and a means for introducing high-frequency power into the reaction vessel. Then, a source gas is introduced into the reaction vessel, high-frequency power is applied, and plasma generated in a discharge space in the reaction vessel is used to form a deposited film on a substrate arranged in the reaction vessel. In the film forming apparatus, a plasma leak preventer is provided between the exhaust port and the discharge space, and at least a part of the plasma leak preventer is provided with a plurality of openings of a size that does not allow plasma to pass through. A deposited film forming apparatus, wherein the surface area of the region is larger than the area of the opening of the exhaust port. 2. The region of the plasma leak preventer in which a plurality of openings are provided is made of punching metal, and the size of each hole of the punching metal is 0.8 m.
m is ² or more 80 mm ² or less, the deposited film forming apparatus according to claim 1 in which the opening ratio of the punching metal is equal to or less than 80% than 20%. 3. The area where the plurality of openings of the plasma leak preventer are provided is made of a metal mesh, and the number of vertical lines on one side of 25.4 mm of the metal mesh is 2.5 or more and 60 or more. The line diameter of the metal mesh is 0.14 mm or more and 5 mm or less, and the deposited film forming apparatus according to claim 1. 4. The plasma leak preventer includes a tubular portion and a flat portion disposed on an end surface of the tubular portion, and at least a part of the tubular portion has a plurality of openings of a size that does not allow plasma to pass therethrough. It is provided, The deposited film forming apparatus of any one of Claim 1 to Claim 3 characterized by the above-mentioned. 5. The deposited film forming apparatus according to claim 4, wherein an insulator is disposed on at least a part of a flat surface portion of the plasma leak preventer. 6. The plasma leak preventer includes a dome portion, and at least a part of the dome portion is provided with a plurality of openings having a size that does not allow plasma to pass therethrough. The deposited film forming apparatus according to claim 3. 7. A plasma generated by applying a high-frequency power from a high-frequency power introducing means by evacuating the inside of a reaction vessel that can be vacuum-tight with an exhaust means, introducing a raw material gas into the reaction vessel. In the deposited film forming method for forming a deposited film on a substrate arranged in a reaction container, the exhaust by the exhaust means passes through a plasma leak preventer provided between an exhaust port of the reaction container and a discharge space. As the plasma leak preventer, at least a part thereof has a region provided with a plurality of openings of a size that does not allow plasma to pass through, and the surface area of the region is the opening of the exhaust port of the reaction vessel. A method for forming a deposited film, characterized in that a plasma leak preventer having a larger area than the above is used.