JP2010242205A - Film-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a film on a plastic container without generating arc discharge and without causing trouble. <P>SOLUTION: This film-forming apparatus has a plurality of main chambers arrayed on a sub-chamber formed of one housing, and accommodates plastic containers with openings in the inside of each main chamber so as to stand upside down, and forms a thin film on all of the plastic containers at the same time with a plasma CVD technique. The film-forming apparatus has also container-neck-supporting components for supporting the plastic containers 1 in the inside of each main chamber by applying such a force to sandwich the neck of the plastic container, arranged in through holes of partition wall plates. Furthermore, the container-neck-supporting component has a function of accommodating the plastic container so as to stand upside down. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for improving film formation stability in an apparatus for forming a film on the inner and outer surfaces of a plastic container in a vacuum range of 100 Pa to 0.5 Pa.

  In general, for the purpose of reducing oxygen permeability and other gas permeability in a plastic container, a carbon film close to the crystal structure of a silicon oxide film or diamond is actively applied to the inner and outer surfaces of the plastic container. When this prescription is applied, the oxygen permeability of a single-layer polyester or polyethylene container is reduced to 1/10 or 1/20, and as a result, the progress of oxidation of the contents is slowed, thereby extending the product life. Quality can be improved. Therefore, it has become possible for a single-layer molded plastic container to enter a region where a multi-layer container is required by using a gas barrier resin such as EVOH or polyamide.

In general, when forming a silicon oxide film, it is well known to use organosiloxane such as hexamethyldisiloxane as a source gas and oxygen as a reaction gas. When a film that enhances the gas barrier property is produced, the gas barrier property with the best crystal structure of silicon dioxide can be obtained. In plasma CVD, a gas barrier film is formed as a deposit of SiO ₂ .

  Conventionally, as a device for forming a film on a plastic container 1 in a vacuum range of 100 Pa to 0.5 Pa, for example, as shown in FIG. 1, a plurality of main chambers 7 are connected to one sub-chamber 8, There is a multi-film forming apparatus that forms a film at once using the plasma CVD method for each plastic container 1 that is stored upside down in each main chamber 7. The advantage of this multi-film deposition system is that the power supply, matching unit, vacuum pump 9 and gas supply unit necessary for film formation can be shared, so that it can be installed in a small place and there is no movement of the chamber. That is less. In addition, since there are few adjustment points, the time from the introduction of the device to the start-up is shorter than that of the continuous rotation type. Above all, the biggest advantage is that the device configuration can be simplified.

  However, as troubles in film formation of the multi-layer film forming apparatus, phenomena such as thermal deformation of the plastic container 1 due to high temperature plasma and carbonization of the plastic container 1 due to arc discharge may be observed. This is mainly due to unevenness in the distribution of the electric field strength caused by the high frequency and microwave applied to the main chamber 7 and the excessive or uneven distribution of gas molecules inside the main chamber 7 or a decrease in exhaust capability. I knew that there was.

  Originally, the plastic container 1 is easy to put in and out, and the mouth portion of the injection-molded plastic container 1 has good dimensional accuracy, so the storage position accuracy is high and the sealing performance with the container support parts is also good. Is the method. However, as shown in FIG. 2, the partition plate 6, which also serves to support the container mouth and shield the plasma from the sub-chamber 8, separates the main chamber 7 from top to bottom, so that the exhaust in the container-side space is exhausted. As a result, the plastic container 1 is thermally deformed and the resin is carbonized due to arc discharge. In order to prevent this, for example, conventionally, as shown in FIG. 3A, exhaust has been performed by providing a gas vent 3 between the partition plate 6 and the main chamber 7. However, although initially good film formation is continued, as the film formation product gradually fills the gap, the staying gas molecules are formed in the plastic container 1 and the partition plate 6 as shown in FIG. Since the air is exhausted from the gap and the electric field strength in this portion is the highest, troubles due to arc discharge have occurred.

The scale of the arc discharge varies depending on the conditions at that time, and the emission intensity of the film-deposited product that seems to be defective at first glance shows a clearly different waveform compared to the normal case, but there are small abnormalities that are difficult to distinguish In some cases, the observation conditions of the light emission intensity in that case may not be confirmed by digital observation unless the interval is 10 nanoseconds or less. A practical problem is an arc discharge abnormality for a very short time that is difficult to identify, and the frequency of occurrence is not steady, and the method of occurrence is very uneven.

  In Patent Document 1, the chamber lid 5 that holds and fixes the bottom of the container is used as a means for inverted storage and transported together with this, thereby eliminating the need to hold the container neck 1a and removing the partition plate 6 to perform arc discharge. It was hard to produce. However, since the sub-chamber 8 and the main chamber 7 are no longer partitioned, the plasma generated in the sub-chamber 8 is likely to enter the plastic container 1 side of the main chamber 7, and a new film property deterioration due to loss of reaction energy. Gave birth to a serious problem.

  Further, Patent Document 2 proposes a container holding part that can be replaced as appropriate, but does not provide a function as a measure against arc discharge, and is made upright by using a plastic container 1 or a cap having a low rigidity. With respect to the designed plastic container 1, there remains a problem with the transport method before and after the film forming apparatus, and a device for solving these problems has been demanded.

  Furthermore, in order to improve the sealing performance between the plastic container 1 and the container holding part, a method of applying a downward load to the bottom of the container via the chamber lid 5 or the like has been tried. As a result, an adverse effect such as a gap on the sealing surface was confirmed.

JP 2008-075143 A JP 2002-371364 A

  Arc discharge is a phenomenon in which resin is carbonized because energy concentrates in a small area like lightning, and often occurs at the start of discharge. The main cause of this phenomenon is due to the gas flowing in a place that is not originally a gas exhaust path. However, the gas seal between the plastic container 1 and the partition plate 6 is poor. Originally, the stretched PET container had sufficient gas sealability due to the high dimensional stability of the container neck 1a. Therefore, it was not necessary to pay special attention to the adhesion of the seal surface. Is slightly deformed, the original gas vent 3 is blocked, and the air remaining in the main chamber 7 seeks a refuge, and the imperfection of the seal becomes apparent.

  That is, in the conventional plastic container film forming apparatus using high-frequency plasma shown in FIG. 2, the container support component shown in FIG. 4 is installed in the through hole of the partition plate 6 of the main chamber 7, and the container support component is placed on the container support component. Mouth support for placing the plastic container 1 was performed. In this case, in the high-frequency plasma, arc discharge is likely to occur around the container mouth having a high electric field strength, and the location tends to be concentrated on the outer surface of the container neck at the contact portion between the plastic container 1 and the container support component of FIG. There was originally a place where no gas was allowed to flow. Conventionally, since a strict gas seal is not applied, if the regular gas vent 3 is clogged with deposits of film formation, gas molecules slightly leak from the gap between the container neck 1a and the container support part of FIG. Thus, dielectric breakdown was caused in combination with a high electric field strength distribution locally.

An object of the present invention is to form a film on the inner surface of a plastic container without any obstacles in the vacuum region of a pressure of 100 Pa to 0.5 Pa without causing an arc discharge.

  In order to solve the above-mentioned problems, the present invention has a plurality of main chambers aligned in a sub-chamber consisting of a single casing, and a plastic container having an opening in each main chamber is stored upside down. The apparatus for forming a thin film by plasma CVD at the same time, and installing a container neck support part for supporting the plastic container by applying a force to sandwich the neck of the plastic container inside each main chamber in the through hole of the partition plate, Furthermore, the container neck support component also has a function of storing the plastic container upside down.

  Further, the present invention provides the film deposition apparatus, wherein the container neck support part has a screw hole that fits into a screw of the neck part of the plastic container, and the plastic container is screwed into the container neck support part for support. The film forming apparatus is characterized in that:

  Further, according to the present invention, in the above film forming apparatus, the container neck support component includes a first component having an undercut shape that facilitates desorption and having a flange on the inside, and the first component is fitted inside. The first part comprises an outer second ring part, and the first part is fitted into the second ring part after the flange of the first part is installed on the flange of the plastic container. The film forming apparatus is characterized in that a force for pinching is applied, and a flange on the inside of the first component is supported by applying a force for pinching the neck of the plastic container.

  Further, the present invention is the film forming apparatus, wherein the container neck support component can be taken in and out of the main chamber in a state of being fitted to the plastic container.

  The present invention improves the sealing performance between the container neck support component and the plastic container by supporting the plastic container 1 by applying a force to sandwich the neck portion of the plastic container with the container neck support component installed in the through hole of the partition plate. The contact portion between the plastic container and the container neck supporting part is reliably sealed, and there is an effect that the abnormal gas flow flowing between the container neck and the container neck supporting part can be eliminated and arc discharge can be suppressed. That is, there is an effect that it is possible to prevent carbonization of the plastic container due to arc discharge by interrupting an abnormal gas flow that is not inherent.

It is a figure explaining the example of a multi-film formation apparatus. It is a figure explaining the example of a main chamber. It is a figure explaining the exhaust flow of the main chamber upper part. It is a figure explaining the example of the conventional container support component. It is a figure explaining the example of the screw-type container neck part support component of this invention. It is a figure explaining the example of the fitting type container neck part support component of this invention.

Hereinafter, an embodiment of the present invention will be described. In the present invention, as shown in FIG. 1, a plurality of main chambers 7 are aligned in a sub-chamber 8 consisting of a single casing, and all the plastic containers 1 housed upside down inside the main chamber 7 are simultaneously plasma-enhanced. This is a multi-film forming apparatus for forming a thin film by the method. The resin structure of the plastic container 1 is a single-layer polyester, polyethylene, polypropylene, or polystyrene, or a multilayer container in which the film formation surface is formed of these resins. Further, the main chamber 7 shown in FIG. 2 includes a cylindrical body having a cylindrical space that can accommodate the plastic container 1 in which a thin film is to be formed inside, and is installed at an open end above the cylindrical body. The main chamber 7 has a partition plate 6 for holding the plastic container 1 on which a thin film is to be formed in a predetermined position, and an external electrode made of a conductive material on the side wall of the cylinder. 4 is installed, and an insulating spacer 2 is installed between the cylindrical body and the plastic container 1. The gas discharge pipe 4 also serving as an internal electrode passes through the opening of the partition plate 6 from the bottom of the main chamber 7 and is held by the container neck support component 10 installed in the through hole of the partition plate 6. It is installed even inside.

  An important feature of the present invention is that in the above-described film forming apparatus, the container neck support component 10 shown in FIG. 5 or 6 is installed in the through hole of the partition plate 6, and the container neck support component 10 is a container of the plastic container 1. This is to support the plastic container 1 by applying a force to sandwich the neck 1a. As a result, the container neck support component 10 has improved sealing performance with the plastic container 1, the contact portion between the plastic container 1 and the container neck support component 10 is securely sealed, and the container neck 1 a and the container neck support component 10 are There is an effect that it is possible to eliminate the abnormal gas flow between them and suppress arc discharge.

  That is, the present invention utilizes the fact that the container neck 1a of the plastic container 1 is designed to be fitted with the cap by applying a force sandwiched between the caps, and the outer surface side is the main chamber. 7 is used, and the inner surface side uses a container neck supporting part 10 that is fitted with the container neck 1a by applying a force to sandwich the container neck 1a of the plastic container 1. The container neck support component 10 is provided with a through hole having a size close to the inner diameter of the mouth so that the film forming gas can be supplied into the plastic container 1 and the gas after the reaction can be discharged. By fitting the container neck support component 10 with the container neck 1a of the plastic container 1, the container neck support component 10 has an effect of providing an airtightness (sealability) with the plastic container 1 and realizing an optimum film forming environment.

  The plastic container 1 and the container neck supporting part 10 can be fitted by a method of fitting by combining the screw 11 of the container neck 1a of the plastic container 1 and the screw hole of the container neck supporting part 10, or the container neck 1a of the plastic container 1. The flange 12 of the container neck and the flange 13 of the container neck support component 10 are brought into contact with each other. An example of the form of each holding component is shown in FIGS. In the shape of FIG. 5, both are screwed together. Thereby, surface sealing is performed at a part of the container neck 1a of the plastic container 1, and there is an effect that the flow of gas flowing along the outer surface of the container neck 1a can be blocked.

  Moreover, in the fitting system of FIG. 6, after installing the flange 13 on the flange 12 of the plastic container 1 after installing the first part having the flange 13 on the inside in the undercut shape that facilitates removal and attachment, Fit the part into the outer second ring part. The first part and the second ring part constitute a container neck support part 10. Thereby, when applying the force which pinches | interposes a 1st component when fitting a 1st component in a 2nd ring component, the force which the flange 13 inside a 1st component pinches | interposes the container neck part 1a of the plastic container 1 To apply. Even if the container neck 1a of the plastic container 1 has the screw 11, if the flange 12 is provided in addition to the screw 11, it can be supported by the container neck support component 10 of the fitting method of FIG. Both container neck support parts 10 are combined with the plastic container 1 outside the film forming apparatus and then inserted into the film forming chamber together with the plastic container 1.

  The above method can be applied to an apparatus for coating a silicon oxide thin film mainly by a plasma CVD method. Regarding the source gas that can be used in this case, hexamethyl disiloxane (hereinafter referred to as HMDSO) as well as trimethylsiloxane can be used as the main gas, thereby forming a silicon oxide thin film. Is possible. In addition to oxygen, ozone, carbon dioxide, or the like can be used as the reactive gas.

  In addition, a gas release pipe 4 for releasing the raw material gas for film formation is provided. When the plastic container 1 is stored in the main chamber 7, the gas release pipe 4 is inserted into the plastic container 1 during insertion. Since the container neck support component 10 can accurately position the plastic container 1, the horizontal displacement of the plastic container 1 is small, and there is an effect of reducing the possibility of interference between the plastic container 1 and the gas discharge pipe 4. Further, when the plastic container 1 is transported while holding the bottom, the container neck support component 10 has an effect of protecting the mouth of the plastic container 1 and preventing the mouth from being damaged. Furthermore, the container neck 1a of the plastic container 1 is supported and the trunk is not held, so that there is an effect that the trunk of the plastic container 1 having low rigidity can be held without applying stress.

Examples of the present invention will be described below.
<Example 1>
A silicon oxide film for enhancing the gas barrier property was generated on the inner surface of a 500 ml PET container by using a plasma CVD film forming apparatus capable of simultaneously forming eight films. As a method of holding the plastic container 1, the plastic container 1 was inserted into the main chamber 7 in an inverted state by using a container neck support component 10 that is coupled with a screw 11 shown in FIG. 5. The main chamber 7 is provided with a partition plate that divides this into upper and lower parts, and is structured to be inverted by inserting a container neck support component 10 into the center thereof. The pressure in the main chamber 7 is changed from 100 Pa to 0. A vacuum region of 5 Pa is used. The plasma generator used a high-frequency power source, and hexamethyldisiloxane (HMDSO) and oxygen were each measured by one mass flow controller and then distributed to each chamber. The vacuum pump 9 relayed one each of a rotary pump, a booster pump, and a turbo molecular pump, and flowed HSCSO at 40 sccm and oxygen at 800 sccm. Then, the film was formed with a high frequency power of 2000 W at a stable flow rate. Table 1 shows the number of occurrences of film formation abnormality when the film is formed 1000 times in total.

<Example 2>
As a method of holding the plastic container 1, a film was formed on the inner wall of the plastic container 1 using a fitting cap type container neck support component 10 shown in FIG. 6. Table 1 shows the number of occurrences of film formation abnormality when the film is formed 1000 times in total.

<Comparative Example 1>
Film formation was performed in the same manner as in Example 1 except that the method for holding the plastic container 1 was a conventional container mouth support. Table 1 shows the number of occurrences of film formation abnormality when the film is formed 1000 times in total.

DESCRIPTION OF SYMBOLS 1 ... Plastic container 1a ... Container neck 2 ... Spacer 3 ... Gas vent 4 ... Gas discharge pipe 5 ... Chamber lid 6 ... Partition plate 7 ... Main chamber 8 ... Sub-chamber 9 ... Vacuum pump 10 ... Container neck support part 11 ... Screw 12 ... Flange of plastic container 13 ... Flange of container neck support part

Claims (4)

  An apparatus in which a plurality of main chambers are aligned in a sub-chamber consisting of a single casing, and a plastic container having an opening is inverted inside each main chamber, and a thin film is simultaneously formed in the plastic container by plasma CVD. A container neck support part for supporting the plastic container by applying a force to sandwich the neck of the plastic container inside each main chamber is installed in the through hole of the partition plate, and the container neck support part inverts the plastic container. A film forming apparatus characterized in that it also has a function of storing.   2. The film forming apparatus according to claim 1, wherein the container neck support part has a screw hole that fits into a screw of the neck part of the plastic container, and the plastic container is supported by screwing into the container neck support part. A characteristic film forming apparatus.   2. The film forming apparatus according to claim 1, wherein the container neck support component is a first component having an undercut shape that facilitates attachment and detachment and has a flange on the inside, and an outer first portion that fits the first component inside. A force that sandwiches the first part by fitting the first part into the second ring part after the flange of the first part is installed on the flange of the plastic container. And the flange on the inner side of the first component supports the film by applying a force to sandwich the neck of the plastic container.   4. The film forming apparatus according to claim 1, wherein the container neck support component can be inserted into and removed from the main chamber in a state of being fitted to the plastic container. apparatus.

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