JP2006111949A - Film deposition system and film deposition method of silicon oxide thin film by cvd process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition system and a film deposition method of a silicon oxide thin film where, in the film deposition of a silicon oxide thin film by a CVD (Chemical Vapor Deposition) process performed as the blending ratio of a gaseous mixture is changed, the time till the flow rates of an organic silicone gas and a gas having oxidizing power reach prescribed ones during film deposition is made short, thus the blending ratio of the gaseous mixture fed into a film deposition chamber is made to rapidly reach a prescribed set value, and film deposition under the gaseous mixture in the prescribed blending ratio is performed in a short time. <P>SOLUTION: The flow rates of gases fed from each of a plurality of mask flow controllers for feeding an organic silicone compound gas and/or a gas having oxidizing power at fixed flow rates are individually set, and further, the organic silicone compound gas and/or the gas having oxidizing power in the fixed flow rates fed from any of the mass flow controllers is selectively fed into a film deposition chamber by change valves, thus a silicon oxide thin film is deposited. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a silicon oxide thin film formed on a surface of a three-dimensional hollow container such as a plastic container, a plastic cup, a plastic tray, a paper container, a paper cup, a paper tray, a glass bottle, and other hollow plastic molded articles by a CVD method (chemical vapor deposition method). The present invention relates to a film forming apparatus and a film forming method for forming a film.

  In recent years, attempts have been made to improve the gas barrier property, water vapor barrier property, surface wettability, and the like of a container by forming a thin film on the surface of a three-dimensional hollow container such as a plastic container. As a method of forming these functional thin films on the surface of the container, there is a film forming method by a plasma assisted CVD method using a chemical reaction of a process gas. Specifically, as shown in Patent Document 1, a container is installed between an external electrode having a hollow portion that is substantially similar to the outer shape of the container and an internal electrode that is approximately similar to the inner shape of the container. A method of forming a film on the surface of the container, and as disclosed in Patent Document 2, the external electrode and the internal electrode are both arranged at a substantially constant distance from the surface of the container, and the film is formed on the surface of the container. It is a method of performing.

  There are various functional thin films formed by these film forming methods, and among these, there are thin films made of silicon oxide. When forming this thin film by the above-mentioned CVD method, it is common to use a mixed gas of an organic silicone gas and a gas having an oxidizing power such as oxygen, and the flow rate of the organic silicone gas and a gas having an oxidizing power. The properties of the silicon oxide thin film are variously changed by appropriately combining the distribution ratios.

  For example, in the film forming method disclosed in Patent Document 3, a portion of a composition having a high carbon atom ratio on the inner surface of the container is appropriately combined with a flow rate and a distribution ratio of an organic silicone gas serving as a source gas and a gas having oxidizing power. By forming a silicon oxide thin film so that a portion having a composition with a low carbon atom ratio is continuously present in a layered manner, a high barrier property can be secured by this thin film, and the container is deformed In addition, the barrier property of the thin film once formed is prevented from deteriorating.

As a method of controlling the raw material gas flow rate when film formation is performed by changing the flow rates of two kinds of raw material gases, the setting value of the mass flow controller used to control the respective gas flow rates is changed during film formation. There is a method, and it is generally used widely. However, the flow control of the mass flow controller is performed by measuring the flow rate of the flowing gas and adjusting the opening of the valve in the mass flow controller by feedback control based on the measured value. Even if it is changed in the film, it takes time for the actual flow rate to reach its set value, so it takes time to obtain a thin film portion having a predetermined composition corresponding to the flow rate set value. It took a long time to form the whole film.
JP-A-8-53117 JP-A-8-175528 JP 2004-124134 A

The present invention has been made to solve the above-described problems of the prior art, and in the formation of a silicon oxide thin film by a CVD method while changing the distribution ratio of the source gas, the organic silicone gas and the oxidizing power are formed during the film formation. By reducing the time until the flow rate of the gas having the predetermined flow rate is reached, the distribution ratio of the source gas supplied into the film forming chamber quickly reaches the predetermined set value, and the predetermined distribution ratio It is an object of the present invention to provide a silicon oxide thin film forming apparatus and a film forming method capable of forming a film under a raw material gas in a short time.

  The present invention has been made to solve such a problem, and the invention according to claim 1 changes the gas distribution ratio by using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power. An apparatus for depositing a silicon oxide thin film on the surface of a container by a CVD method, having a plurality of mass flow controllers for supplying an organosilicon compound gas at a constant flow rate, and of these mass flow controllers A film-forming apparatus for a silicon oxide thin film by a CVD method, characterized in that a switching valve is provided for supplying a constant flow rate organosilicon compound gas sent from one into the film-forming chamber. is there.

  According to the second aspect of the present invention, a silicon oxide thin film is formed on the surface of a container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing a gas distribution ratio. A plurality of mass flow controllers for supplying a gas having oxidizing power at a constant flow rate, and a constant flow oxidizing power sent from one of these mass flow controllers. This is a silicon oxide thin film deposition apparatus by a CVD method, in which a switching valve is provided for allowing a gas to be supplied into the deposition chamber.

  Furthermore, in the invention described in claim 3, a silicon oxide thin film is formed on the surface of the container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing the gas distribution ratio. An apparatus for forming a membrane having a plurality of mass flow controllers for supplying an organosilicon compound gas at a constant flow rate and a plurality of mass flow controllers for supplying a gas having oxidizing power at a constant flow rate; and A switching valve for allowing a constant flow rate organosilicon compound gas supplied from one of the plurality of mass flow controllers to be supplied into the film forming chamber and one of the plurality of mass flow controllers. Switching to be able to supply the gas having a constant flow rate of oxidizing power into the deposition chamber It is the film forming apparatus of the silicon oxide film by the CVD method, characterized in that the valve is installed.

  Furthermore, in the invention described in claim 4, a silicon oxide thin film is formed on the surface of the container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing the gas distribution ratio. In the film forming method for forming a film, individually setting the gas flow rate sent from each of a plurality of mass flow controllers for supplying each of the organic silicone compound gas and the gas having oxidizing power at a constant flow rate, Switch between a constant flow rate organosilicon compound gas sent from one of the mass flow controllers and / or a constant flow rate oxidizing gas sent from one of the mass flow controllers. By selecting and supplying into the deposition chamber by switching the valve, the distribution ratio of the mixed gas can be adjusted. A method of forming a silicon oxide thin film characterized in that so as to deposit a silicon oxide film while reduction.

In the present invention, in the formation of the silicon oxide thin film by the CVD method while changing the distribution ratio of the source gas, by changing the mixing ratio of the source gas during the film formation in cooperation with the mass flow controller and the switching valve, During the film formation, the time until the flow rate of the organic silicone gas and the gas having oxidizing power reaches a predetermined flow rate is shortened, and the distribution ratio of the source gas in the film formation chamber quickly reaches the predetermined set value. Therefore, it is possible to form a silicon oxide thin film in which a desired composition portion is changed into a layer shape in a short time.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing an example of a silicon oxide thin film forming apparatus according to the CDV method of the present invention used for forming a silicon oxide thin film on the inner surface of a plastic container.

  This apparatus generally includes a film formation chamber 17, a gas introduction pipe 7 for supplying a mixed gas containing at least an organic silicone compound gas and a gas having an oxidizing power into the film formation chamber 17, and an organic silicone. A plurality of mass flow controllers 11 and 12 for supplying compound gas at a constant flow rate, a plurality of mass flow controllers 13 and 14 for supplying gas having oxidizing power at a constant flow rate, and mass flow controllers 11 and 12 respectively. Are sent from a switching valve 15 for supplying only one of the source gases (organosilicone compound gas) sent from the inside of the film forming chamber 17 via the gas supply pipe 7 and the mass flow controllers 13 and 14, respectively. Only one of the incoming raw material gases (gas having oxidizing power) passes through the gas supply pipe 7 It comprises a switching valve 16 for supplying the membrane chamber 17, source gas storage units 9, 10 for storing source gas, and a plurality of source gas transport pipes 19, 19. .

  The film forming chamber 17 has a cylindrical space that can accommodate the container 1 in which a thin film is to be formed, and is disposed at the external electrode 2 made of a conductive material and one open end of the external electrode 2. And a bottom cover 5 disposed at the other opening end, and an exhaust port 4 is provided in a part of the bottom cover 5. In the position, a container holding portion 6 for arranging the container 1 is provided by an insulator. A gas introduction tube 7 which is a hollow tube is inserted and arranged in the film forming chamber 17, and at least an organosilicon compound gas and a gas having an oxidizing power are mixed from the mixed gas discharge port 8 at the tip thereof with a predetermined composition. A mixed gas contained in a ratio is supplied into the container 1. In addition, a vacuum pump (not shown) is installed through the exhaust port 4 in order to evacuate the film forming chamber 17.

  In the film forming apparatus having such a configuration, the organosilicon compound gas stored in the source gas storage unit 9 is sent to the mass flow controllers 11 and 12 through the gas transport pipe and stored in the source gas storage unit 10. The organic silicone compound gas is sent to the mass flow controllers 13 and 14 through the gas transport pipe. Each mass flow controller 11, 12, 13, 14 has an internal valve opening adjusted to an appropriate one, and from the mass flow controllers 11, 12, an organic silicone compound gas at a constant flow rate corresponding to the valve opening is obtained. Gas having a constant flow rate of oxidizing power corresponding to the opening of the valve is sent from the mass flow controllers 13 and 14 to the switching valve 16 via the gas transport pipe. Will be sent.

  Then, in the switching valve 15, one of a predetermined flow rate of the organosilicon compound gas sent from either of the mass flow controllers 11, 12 by switching the valve, and in the switching valve 16, which of the mass flow controllers 13, 14 is switched by switching the valve. Control is performed so as to feed one of the gases having a predetermined flow rate of oxidizing power sent from the head toward the gas introduction pipe 7.

Under such control, for example, a silicon oxide thin film is formed on the surface of the container 1 so that a portion having a high carbon atom ratio and a portion having a low carbon atom ratio are continuously present in layers. In such a case, the flow rate setting of the mass flow controller 11 is increased, the flow rate setting of the mass flow controller 12 is decreased, and the switching valve 15 is switched instantaneously at a predetermined timing during film formation, so that Switch the mass flow controller related to the supply, change the compounding ratio of the organosilicon compound gas in the mixed gas supplied into the container 1 in a short time, and as a result, the composition part with a high carbon atom ratio and the carbon atom ratio It is possible to form a silicon oxide thin film in which a portion having a low composition is continuously laminated in a layered manner in a short time. This is because, if the ratio of the organosilicon compound gas in the mixed gas is high, a part having a composition containing a large amount of carbon atoms can be obtained, and conversely, if the ratio of the organosilicon compound is low, a part having few carbon atoms can be obtained. By appropriately changing the gas distribution ratio between the organic silicone compound gas and the gas having oxidizing power during the formation of the thin film, a portion having a high carbon atom ratio and a portion having a low carbon atom ratio are layered. This utilizes the phenomenon that a continuously existing silicon oxide thin film is formed.

  Therefore, in order to form a film by gradually changing the composition in the thickness direction of the silicon oxide thin film to be formed, even if the flow rate of the oxidizing gas is changed while the flow rate of the organosilicon compound gas is kept constant, Alternatively, the gas flow rate of the organic silicone compound may be changed while keeping the flow rate of the gas having oxidizing power constant.

  In actual film formation, after the inside of the film formation chamber 17 is kept at a certain degree of vacuum, high-frequency power is supplied to the external electrode 2 while supplying the mixed gas from the mixed gas discharge port 8 of the gas introduction pipe while adjusting the gas as described above. When applied, the gas in the bottle 1 is turned into plasma, and a silicon oxide thin film in which a predetermined composition portion changes into a layer shape on the inner surface of the container can be efficiently formed.

  Examples of the organic silicone compound gas used in this case include 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethoxysilane, hexamethyldisilane, methylsilane, dimethylsilane, In gases such as trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane An appropriate one can be selected from the above. Of these, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, and octamethylcyclotetrasiloxane are preferred. However, the organic silicone compound gas that can be used in the present invention is not limited to these organic silicone compound gases, and gases such as aminosilane and silazane can also be used.

  As the gas having oxidizing power, for example, oxygen, carbon monoxide, carbon dioxide, ozone and the like can be used. Examples of the present invention will be described below.

  A hollow container 1 made of polyethylene terephthalate having a capacity of 500 ml was set in the container holding part 6 installed in the film forming chamber 17 of the film forming apparatus shown in FIG. Next, the flow rates of the mass flow controller 11 (MFC 11), the mass flow controller 12 (MFC 12), and the mass flow controller 21 (MFC 21) are set as shown in Table 1, and the switching valve 15 is switched so that the source gas storage unit 9 The stored hexamethyldisiloxane gas, and the oxygen gas stored in the source gas storage unit 10 via the switching valve 16 are supplied into the film forming chamber 17 while being controlled as follows. A silicon oxide thin film was formed.

The film formation time when the mixed gas was supplied from the gas discharge port 8 of the gas introduction pipe 7 was 5 seconds in total, but during that time, the gas flow of hexamethyldisiloxane was a mass flow controller for 2 seconds from the start of film formation. 11 (MFC11), and then the switching valve 15 was switched and then supplied via the mass flow controller 12 (MFC12) for 3 seconds. In addition, oxygen gas was supplied for 5 seconds via the mass flow controller 21 (MFC 21) without switching the switching valve 16. Further, the high frequency power applied to the external electrode 2 during film formation was 400 watts.

  The flow rates of the mass flow controller 11 (MFC 11), the mass flow controller 21 (MFC 21), and the mass flow controller 22 (MFC 22) are set as shown in Table 1 and stored in the source gas storage unit 9 via the switching valve 15. The oxygen gas stored in the source gas storage unit 10 is supplied from the gas introduction pipe 7 into the film forming chamber 17 while being controlled as follows by switching the gas of hexamethyldisiloxane and switching the switching valve 16. Then, a silicon oxide thin film was formed.

  The film formation time performed by supplying the mixed gas from the gas discharge port 8 of the gas introduction pipe 7 was 5 seconds as a whole. During this time, the mass flow controller was used for the hexamethyldisiloxane gas without switching the switching valve 15. 11 (MFC11) is supplied for 5 seconds, oxygen gas is not supplied for 2 seconds from the start of film formation, and the changeover valve 16 is switched after 2 seconds for 3 seconds from the mass flow controller 21 (MFC21). Supply was made. The other conditions were the same as in Example 1.

  The flow rates of the mass flow controller 11 (MFC 11), the mass flow controller 12 (MFC 12), and the mass flow controller 22 (MFC 22) are set as shown in Table 1 and stored in the source gas storage unit 9 by switching the switching valve 15. The oxygen gas stored in the source gas storage unit 10 is supplied from the gas introduction pipe 7 into the film forming chamber 17 while being controlled as follows by switching the hexamethyldisiloxane gas and the switching valve 16. Then, a silicon oxide thin film was formed.

  The film formation time when the mixed gas was supplied from the gas discharge port 8 of the gas introduction pipe 7 was 5 seconds in total, but during that time, the gas flow of hexamethyldisiloxane was a mass flow controller for 2 seconds from the start of film formation. 11 (MFC11), and then the switching valve 15 is switched to supply the massflow controller 12 (MFC12) for 3 seconds.

  On the other hand, oxygen gas was not supplied for 2 seconds from the start of film formation, and was supplied from the mass flow controller 22 (MFC 22) for 3 seconds by switching the replacement valve 16 after 2 seconds had elapsed. The other conditions were the same as in Example 1.

  Using the same film forming apparatus as in Example 1, the mass flow controller 12 (MFC 12), the mass flow controller 22 (MFC 22), and the switching valves 15 and 16 are not used, and the mass flow controller 11 (MFC 11) and the mass flow controller 21 (MFC 21). The mass flow controller 11 (MFC11) supplied hexamethyldisiloxane gas at 10 SCCM for 2 seconds from the start of film formation and then at 2 SCCM for 3 seconds, and at the same time, the mass flow controller 21 ( While the oxygen gas was supplied from the MFC 21) into the film forming chamber 17 for 5 seconds, film formation according to Example 4 for comparison was performed. Control of the flow rate in the mass flow controller 11 (MFC11) was performed by measuring the flow rate of the flowing gas and adjusting the valve opening of the massflow controller 11 (MFC11) by feedback control based on the measured value.

  The ratio of carbon atoms in the total number of atoms of carbon, silicon, and oxygen in the silicon oxide thin film obtained by the film formation according to Examples 1 to 4 performed as described above was measured in the thickness direction. The results are shown in FIG. In the silicon oxide thin films according to Examples 1 to 3, the ratio of carbon atoms in the thin film changed rapidly in response to the change in gas flow rate from the time when the gas flow rate of hexamethyldisiloxane was changed. However, the silicon oxide thin film according to Example 4 did not change abruptly as the gas flow rate of hexamethyldisiloxane was changed, but only changed gently.

It is a schematic explanatory drawing which shows an example of the film-forming apparatus of the silicon oxide thin film by CVD method of this invention. It is explanatory drawing which shows the distribution ratio of the carbon atom in the thickness direction of the silicon oxide thin film in each Example, and the relationship of a film thickness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container 2 ... External electrode 3 ... Canopy 4 ... Exhaust port 5 ... Bottom cover 6 ... Container holding component 7 ... Gas introduction pipe 8 ... Mixed gas discharge port 9, 10 ... Raw material gas storage 11, 12, 13, 14 ... Mass flow controllers 15, 16 ... Switching valve 17 ... Deposition chamber

Claims (4)

  An apparatus for forming a silicon oxide thin film on the surface of a container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing a gas distribution ratio, the organosilicon compound A plurality of mass flow controllers for supplying gas at a constant flow rate, and a constant flow rate organosilicon compound gas sent from one of these mass flow controllers can be supplied into the film forming chamber. An apparatus for forming a silicon oxide thin film by a CVD method, characterized in that a switching valve is provided.   An apparatus for forming a silicon oxide thin film on the surface of a container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing the gas distribution ratio. A plurality of mass flow controllers for supplying the gas having a constant flow rate, and a gas having a constant flow oxidizing power sent from one of these mass flow controllers can be supplied into the film forming chamber. An apparatus for forming a silicon oxide thin film by a CVD method, characterized in that a switching valve is provided for the purpose of CVD.   An apparatus for forming a silicon oxide thin film on the surface of a container by a CVD method using a mixed gas containing at least an organosilicon compound gas and a gas having an oxidizing power while changing a gas distribution ratio, the organosilicon compound It has a plurality of mass flow controllers for supplying gas at a constant flow rate and a plurality of mass flow controllers for supplying gas having oxidizing power at a constant flow rate, and is sent from one of the plurality of mass flow controllers. A gas having a constant flow rate of oxidizing power sent from one of a plurality of mass flow controllers and a switching valve for enabling a constant flow rate of organosilicon compound gas to be supplied into the film forming chamber. A switching valve is installed to enable supply to the film formation chamber. Film forming apparatus of the silicon oxide film by CVD that.   In a film forming method for forming a silicon oxide thin film on the surface of a container by a CVD method using a mixed gas containing at least an organic silicone compound gas and a gas having oxidizing power while changing the gas distribution ratio, A gas flow rate is individually set from each of a plurality of mass flow controllers for supplying a gas and a gas having oxidizing power at a constant flow rate, and is sent from one of the plurality of mass flow controllers. A constant flow rate organosilicon compound gas and / or a constant flow rate oxidizing gas sent from one of a plurality of mass flow controllers is selected in the deposition chamber by switching the switching valve. By supplying the silicon oxide thin film, the distribution ratio of the mixed gas is changed. Method of forming a silicon oxide thin film characterized in that there was Unishi.

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