JP2006117962A - Apparatus for depositing thin film on three-dimensional hollow container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for depositing a thin film on a three-dimensional hollow container. <P>SOLUTION: The apparatus for depositing the thin film on the three-dimensional hollow container comprises a cylindrical metallic container to seal the microwave energy, a non-metallic vacuum chamber to store a hollow container for which a film is deposited, in the cylindrical metallic container, and a means which has a raw material gas introduction pipe to fill a raw material gas into the hollow container and fill the microwave energy via a microwave transmission means of an axial line structure installed on a top part of the cylindrical metallic container. The microwave energy is filled in the cylindrical metallic container by at least one strip line in which the microwave energy filling means is present with an inner face of the cylindrical metallic container as a grounding face, and the raw material gas can be changed into plasma state by using the plasma obtained by the energy. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

 The present invention uses microwave plasma on the surface of three-dimensional hollow containers such as plastic bottles, plastic cups, plastic trays, paper containers, paper cups, paper trays, and other hollow plastic molded products to process the raw material gas into plasma. The present invention relates to a thin film forming apparatus for a three-dimensional hollow container that forms a thin film by performing processing.

Recently, hollow containers are required to have various functions in various fields such as the food field and the pharmaceutical field. Among them, plastic containers are widely used as packaging containers because of their light weight and low cost. In recent years, various techniques for coating a plastic container have been developed in particular in order to provide a barrier property, and plastic containers having a barrier thin film formed by these techniques are widely available. (For example, see Patent Documents 1 and 2.)
As a method for forming a barrier thin film, generally, an object to be deposited is arranged inside using a hollow resonator having a cylindrical structure, a source gas is injected, microwave energy is further injected, and plasma is generated by the energy. Film formation is performed by gas. At this time, the key points are how to efficiently inject microwave energy into the cavity resonator and make the electromagnetic field distribution of the microwave as uniform as possible. The resonance frequency and resonance mode in a cylindrical cavity resonator can usually be determined by calculation based on the inner diameter and height of the resonator, the internal dielectric constant, etc. The resonance state as designed cannot be obtained with the change of the electrical physical constant of the material.

  The apparatus configuration in Patent Document 1 is a method of injecting microwaves from the top surface side of a cylindrical cavity resonator. However, since the plasma generation unit is basically a cavity resonator type, the microwave supply portion and the cavity resonance are used. There is some distance between them and a mode conversion for microwave energy transmission is required. However, the electromagnetic field distribution in the cavity resonator is also affected by the electromagnetic field distribution in this mode conversion part, which is different from the electromagnetic field distribution in the original cavity resonator alone, and the intensity of the generated plasma The distribution is also affected, and the film formation result is also changed. Further, in this mode conversion portion, the electromagnetic field distribution also changes with the change of the film formation target and the gas introduction pipe, and this also affects the plasma distribution and the film formation result. Even if this electromagnetic field distribution is analyzed using commercially available simulation software, a strong electric field distribution is present between the microwave supply section and the gas introduction tube. Due to the presence of an electric field, a very strong plasma is generated in this part, and the heat balance in the hollow container is broken, and only this part may be deformed.

  For the purpose of improving the film formation result accompanying the film formation object change, an apparatus configuration as in Patent Document 2 is also considered in the prior art. In Patent Document 2, a cylindrical conductor is inserted around a film formation target so as to obtain a good film formation result corresponding to a film formation target having various shapes and dimensions, and an optimum electromagnetic field is obtained. Try to get the distribution. However, in order to deal with various film formation target shapes, the shape of the cylindrical conductor must be examined each time, and lacks versatility.

Patent documents are shown below.
Special table 2003-518555 gazette Special table 2003-534627 gazette

  The present invention has been made to solve the problems of the above-described technology, and in any film formation target, microwave energy is generated from a strip line in which an inner surface of a cylindrical metal container is an earth surface. An object of the present invention is to provide a thin film forming apparatus for a three-dimensional hollow container, characterized in that a thin film is formed by converting a raw material gas into plasma using plasma radiated into the container and obtained from this energy. To do.

In order to achieve the above purpose, that is,
The invention according to claim 1 of the present invention is
A cylindrical metal container that contains microwave energy, a non-metallic vacuum chamber that houses a hollow container that is a film formation target in the cylindrical metal container, and a source gas that injects a source gas into the hollow container An introduction pipe is disposed, and a means for injecting microwave energy through a microwave transmission means having a coaxial line structure is provided in the top surface portion of the cylindrical metal container, and the microwave energy injection means is the cylindrical metal Microwave energy is injected into the cylindrical metal container by at least one strip line that can exist as an earth surface on the inner surface of the container, and the raw material gas is generated using plasma obtained by this energy. Is a thin film deposition apparatus for a three-dimensional hollow container.

The invention according to claim 2
A raw material gas introduction pipe for containing a hollow container as a film formation object in a cylindrical metal container capable of containing microwave energy and keeping the inside in a vacuum state, and injecting a raw material gas into the hollow container Disposed on the top surface portion of the cylindrical metal container, and having means for injecting microwave energy via a microwave transmission means having a coaxial line structure, the microwave energy injection means being provided in the cylindrical metal container. Microwave energy is injected into the cylindrical metal container by at least one strip line which can exist as an earth surface on the inner surface, and the raw material gas is converted into plasma using plasma obtained by this energy. This is a thin film deposition apparatus for a three-dimensional hollow container.

The invention described in claim 3
The thin film deposition apparatus for a three-dimensional hollow container according to claim 1 or 2,
A thin film deposition apparatus for a three-dimensional hollow container, wherein the plurality of strip lines are arranged radially around a feeding point of the coaxial line.

The invention according to claim 4
The thin film deposition apparatus for a three-dimensional hollow container according to any one of claims 1 to 3,
A thin film deposition apparatus for a three-dimensional hollow container, characterized in that the strip line is disposed so as to be covered with a metal plate from a feeding point of the coaxial line to an arbitrary position, and the metal plate is at ground potential. .

The invention according to claim 5
The thin film deposition apparatus for a three-dimensional hollow container according to claim 3,
A thin film deposition apparatus for a three-dimensional hollow container, wherein the length of the strip line is an integral multiple of a half wavelength of an electromagnetic wave used from the feeding point of the coaxial line, and further within a range of ± 20% It is.

The invention described in claim 6
The thin film deposition apparatus for a three-dimensional hollow container according to claim 4,
The length of the exposed portion of the strip line covered with the metal plate at the ground potential is an integral multiple of the half wavelength of the electromagnetic wave used, and is within a range of ± 20%. Is a thin film deposition apparatus for a three-dimensional hollow container.

The invention described in claim 7
In the thin film formation apparatus of the three-dimensional hollow container according to any one of claims 1 to 6,
A thin film forming apparatus for a three-dimensional hollow container, wherein a thin film is formed by a plasma CVD method.

In the present invention, for example, as shown in FIGS. 1 to 4, a cylindrical metal container for containing microwave energy, and a hollow container which is a film formation object are accommodated in the cylindrical metal container, and the hollow container contains the container. A raw material gas introduction pipe for injecting the raw material gas is disposed, and further, an exhaust port for maintaining a vacuum state by a vacuum pump (not shown) is provided on the bottom surface of the cylindrical metal container, and the inside of the cylindrical metal container In a thin film deposition apparatus for a three-dimensional hollow container that forms a thin film by a plasma CVD method, for example, in which microwave energy is injected into the plasma and the raw material gas is converted into plasma using plasma obtained by this energy.
As a means for injecting microwave energy, a microwave transmission means having a coaxial line structure is provided on the top surface of the cylindrical metal container, and the inner surface of the cylindrical metal container is formed from the feeding point of the coaxial line as a ground plane. By using an apparatus configuration in which microwave energy is radiated into the cylindrical metal container using at least one strip line, a stable microwave electromagnetic field distribution inside the cylindrical metal container. As a result, a thin film can be stably and uniformly formed on the three-dimensional hollow container.

  In addition, if the hollow container can be accommodated in the cylindrical metal container, there is no significant change in the electromagnetic field distribution in the cylindrical metal container, so to some extent against changes in various shapes and dimensions, Stable and good film formation results can be obtained.

  Hereinafter, the basic configuration of the thin film deposition apparatus for a three-dimensional hollow container according to the present invention will be described with reference to FIGS. 1 to 4, but is not limited thereto.

First, FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a perspective view. A non-metallic vacuum chamber 2 that houses a hollow container 3 that is a film formation target is disposed inside a cylindrical metal container 1 that mainly contains microwave energy, and a raw material gas is injected into the hollow container inside. A source gas introduction pipe 4 to be inserted is inserted from the bottom surface of the cylindrical metal container 1, and an exhaust port 5 for evacuating the metal container is provided at the bottom surface.
In order to inject microwave energy into the top surface portion of the cylindrical metal container 1 through the microwave transmission means having the coaxial line 6 structure, the inner surface of the cylindrical metal container 1 may exist as a ground plane. At least one or more strip lines 7 that can be formed are arranged radially extending from the feeding point of the coaxial line 6. In FIG. 2, the strip line 7 is configured as four lines, but the present invention is not limited to this. By making the tip of the strip line 7 open with respect to the ground potential surface, a standing wave is generated on the strip line, so that microwave energy is radiated into the cylindrical metal container.

  Since each strip line 7 has the same length and is uniformly arranged radially in the cylindrical container, the electromagnetic field distribution in the cylindrical metal container 1 is always in a constant distribution form. Although a thin film is formed on a three-dimensional hollow container by CVD using plasma obtained by microwave energy by this electromagnetic field distribution, the film formation result is always stable because the electromagnetic field distribution is constant. Also, uniformity of film formation can be obtained.

  FIG. 3 is a side sectional view showing another embodiment of the present invention. Basically, like FIG. 1 and FIG. 2, a hollow container 3 as a film forming object is arranged inside a cylindrical metal container 1, and a raw material gas introduction pipe 4 for injecting a raw material gas into the hollow container. Is inserted from the bottom surface of the cylindrical metal container 1, and the bottom surface is provided with an exhaust port 5 for evacuating the metal container.

However, the non-metallic vacuum chamber 2 that houses the hollow container 3 as shown in FIGS. 1 and 2 is not used, and the entire inside of the cylindrical metallic container 1 is evacuated. Therefore, it is necessary to have a structure in which the coaxial line 6 portion, which is a microwave introduction portion, is also vacuum-sealed.
As means for injecting microwave energy, microwave energy is injected from the top surface of the cylindrical metal container 1 through microwave transmission means having a coaxial line 6 structure, as in FIGS. In addition, at least one strip line 7 that can exist with the inner surface of the cylindrical metal container 1 as a ground plane is radially extended from the feeding point of the coaxial line 6. By making the tip of the strip line 7 open with respect to the ground potential surface, a standing wave is generated on the strip line, so that microwave energy is radiated into the cylindrical metal container.

  Since each strip line 7 has the same length and is uniformly arranged radially in the cylindrical container, the electromagnetic field distribution in the cylindrical metal container 1 is always in a constant distribution form. Although a thin film is formed on a three-dimensional hollow container by CVD using plasma obtained by microwave energy by this electromagnetic field distribution, the film formation result is always stable because the electromagnetic field distribution is constant. Also, uniformity of film formation can be obtained.

  FIG. 4 is a side sectional view showing still another embodiment of the present invention. 1, 2, and 3, the strip line 7 is connected to a feeding point of a coaxial line portion 6 that transmits and injects microwave energy, and is made of a cylindrical metal from the feeding point to an arbitrary position. Covered with the same earth shield conductor 8 as the inner surface potential of the container 1 and disposed at a position where the distance between the strip line 7 and the inner surface of the cylindrical metal container 1 and the distance between the strip line 7 and the earth shield conductor 8 are substantially equal. Has been. This is a structure similar to a coplanar transmission system in a microwave transmission system.

  The purpose of arranging the earth shield conductor 8 is to suppress microwave radiation to unnecessary portions in the cylindrical metal container, and to further improve the uniformity of film formation. In particular, as shown in FIG. 3, in the apparatus configuration in which the inside of the cylindrical metal container 1 is evacuated and microwave energy is applied to generate plasma in the hollow container, pressure, microwave power, gas Depending on the conditions, plasma may be generated outside the hollow container. This is because the influence of microwave radiation from the strip line 7 from the feeding point of the coaxial line 6 to a specific range is great. Therefore, in FIG. 4, the strip line 7 in the unnecessary part outside the plasma generation (film formation area) is shielded by the earth shield conductor 8 to suppress unnecessary radiation.

  This effect is particularly effective in an apparatus configuration that does not use the vacuum chamber 2 as shown in FIG. 3, but is also effective in plasma discharge control in the upper portion of the vacuum chamber 2 in the apparatus configuration as shown in FIGS. .

  Here, the microwave energy supply from the generation of the microwave to the inside of the cylindrical metal container 1 will be described with reference to FIG.

A microwave is generated by a microwave oscillator 9, and a magnetron having an oscillation frequency of 2.45 GHz is generally used as the oscillation source, but there is no problem with another frequency.
Then, the microwave is guided to the load side (film forming apparatus side) through the matching unit 11 using the rectangular waveguide 10. As described above, the part that directly transmits the microwave energy to the film forming apparatus is the coaxial line 6, but it is necessary to convert the transmission mode of the coaxial line 6 and the transmission mode in the waveguide. There is a portion that fulfills the function of the waveguide coaxial conversion section 12. This is a structure in which the central conductor of the coaxial line 6 has entered the center of the rectangular waveguide 10, where microwaves are excited and travel in the direction of the coaxial line 6.

  The matching unit 11 matches the impedance viewed from the waveguide coaxial conversion unit 12 side and the impedance viewed from the microwave oscillator 9 side from the position of the matching unit 11 in the rectangular waveguide 10, and the microwave oscillator 9. Adjustment is made so as to achieve matching so that a reflected wave to the side does not occur. If this reflected wave is large, sufficient microwave energy cannot be injected into the film forming apparatus and plasma is not generated. At the same time, the reflected wave may damage the magnetron that is the oscillation source. In general, a stub tuner or an E-H tuner is used as the matching unit 11.

  3 and 4, the illustration of the microwave supply portion to the apparatus is omitted, but it can be easily imagined that an apparatus similar to that shown in FIG. 1 is used.

  Further, a plurality of radial strips formed from the top surface portion of the cylindrical metal container 1 through the transmission means of the coaxial line structure and from the feeding point of the coaxial line 6 to the inner surface of the cylindrical metal container 1 as the ground plane. Since the device configuration is such that microwave energy is radiated to the central part of the cylindrical metal container using the line 7, a stable electromagnetic field distribution can always be obtained, and thus a hollow that can be stored in the cylindrical metal container. In the case of a container, there is no significant change in the electromagnetic field distribution in the cylindrical metal container, so that a stable and good film formation result can be obtained to some extent even with changes in various shapes and dimensions.

It is a sectional side view which shows an example of the Example in the thin film film-forming apparatus in this invention. It is a perspective view which shows an example of the Example in the thin film film-forming apparatus in this invention. It is a sectional side view which shows another example of the Example in the thin film film-forming apparatus in this invention. It is a sectional side view which shows another example of the Example in the thin film film-forming apparatus in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylindrical metal container 2 ... Nonmetallic vacuum chamber 3 ... Three-dimensional hollow container (film formation object)
4 ... Raw material gas introduction pipe 5 ... Exhaust port 6 ... Coaxial line 7 ... Strip line 8 ... Earth shield conductor 9 ... Microwave oscillator 10 ... Rectangular waveguide 11 ..Matching unit 12: waveguide coaxial conversion section

Claims (7)

  A cylindrical metal container that contains microwave energy, a non-metallic vacuum chamber that houses a hollow container that is a film formation target in the cylindrical metal container, and a source gas that injects a source gas into the hollow container An introduction pipe is disposed, and a means for injecting microwave energy through a microwave transmission means having a coaxial line structure is provided in the top surface portion of the cylindrical metal container, and the microwave energy injection means is the cylindrical metal Microwave energy is injected into the cylindrical metal container by at least one strip line which can exist as an earth surface on the inner surface of the container, and the raw material gas is generated using plasma obtained by this energy. A thin film deposition apparatus for a three-dimensional hollow container, characterized in that the plasma is converted into plasma.   A raw material gas introduction pipe for containing a hollow container as a film formation object in a cylindrical metal container capable of containing microwave energy and keeping the inside in a vacuum state, and injecting a raw material gas into the hollow container The cylindrical metal container is provided with means for injecting microwave energy into the top surface of the cylindrical metal container via a microwave transmission means having a coaxial line structure, and the microwave energy injection means is provided on the cylindrical metal container. Microwave energy is injected into the cylindrical metal container by at least one strip line which can exist as an earth surface on the inner surface, and the raw material gas is converted into plasma using plasma obtained by this energy. A thin film forming apparatus for a three-dimensional hollow container. The thin film deposition apparatus for a three-dimensional hollow container according to claim 1 or 2,
A thin film deposition apparatus for a three-dimensional hollow container, wherein the plurality of strip lines are arranged radially about a feeding point of the coaxial line. The thin film deposition apparatus for a three-dimensional hollow container according to any one of claims 1 to 3,
3. A thin film deposition apparatus for a three-dimensional hollow container, wherein the strip line is disposed so as to be covered with a metal plate from a feeding point of the coaxial line to an arbitrary position, and the metal plate is at ground potential. The thin film deposition apparatus for a three-dimensional hollow container according to claim 3,
A thin film deposition apparatus for a three-dimensional hollow container, wherein the length of the strip line is an integral multiple of a half wavelength of an electromagnetic wave used from the feeding point of the coaxial line, and further within a range of ± 20% . The thin film deposition apparatus for a three-dimensional hollow container according to claim 4,
The length of the exposed portion of the strip line covered with the metal plate at the ground potential is an integral multiple of the half wavelength of the electromagnetic wave used, and is within a range of ± 20%. A thin film deposition apparatus for a three-dimensional hollow container. In the thin film formation apparatus of the three-dimensional hollow container according to any one of claims 1 to 6,
A thin film forming apparatus for a three-dimensional hollow container, characterized in that a thin film is formed by a plasma CVD method.

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