JP4023775B2 - Diamond-like carbon film deposition equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film forming equipment for forming a diamond-like carbon film on a film-like or sheet-like object to be processed surface.
[0002]
[Prior art]
Diamond-like carbon film is amorphous carbon mainly composed of SP ³ bonds between carbons, and has excellent gas barrier properties, low friction, high hardness, high electrical insulation, high refractive index, high heat dissipation, high corrosion resistance, etc. It is a hard carbon film with physical and chemical characteristics.
[0003]
A diamond atmosphere is formed on the surface of the object by maintaining a vacuum atmosphere between the electrodes facing each other, positioning the object to be processed between the electrodes, introducing a raw material gas, and generating a plasma by applying a high frequency. A like carbon film is formed.
[0004]
Therefore, if this film is coated on beverage containers such as PET bottles, infusion soft bags and packaging films, the high gas barrier property not only prevents the contents from being altered, but also increases the mechanical strength. The coating can be used for a wide range of applications, such as improving heat dissipation and electrical insulation, and coating metal to make it difficult to corrode.
[0005]
[Problems to be solved by the invention]
However, conventionally, the vacuum chamber in which the electrodes are arranged is placed in a high vacuum atmosphere of about 10 ⁻³ to 10 ⁻² Pa to eliminate internal impurities, and then the adhesion of the diamond-like carbon film to the surface of the workpiece is improved. After introducing argon gas to improve the surface and plasma-treating the surface, a diamond-like carbon film is formed by introducing a source gas between the electrodes and applying a high frequency to generate plasma. Yes.
[0006]
Therefore, there is a problem that not only the vacuum chamber must be formed in a high vacuum pressure-resistant vessel, but also the vacuum pump is increased in size, the airtightness of the exhaust system is required, and time and energy are required for exhaustion.
In particular, when a diamond-like carbon film is continuously formed on a film wound on a roll such as a plastic film that is a raw material for an infusion bag, in order to eliminate impurities in the vacuum chamber, the inside is 10 ^{− Since} it is necessary to create a high vacuum atmosphere of about ³ to 10 ⁻² Pa, the vacuum chamber must be completely sealed, and therefore accommodates all film unwinding rolls and winding rolls. Had to get very large to get.
[0007]
In addition, in order to improve the adhesion of the diamond-like carbon film, conventionally, plasma treatment is performed by introducing argon gas. This pretreatment is effective when the object to be treated is a metal, but it is non-metallic. In particular, in the case of a soft material such as plastic, the adhesion is not necessarily improved, and there are some which are easily dropped after film formation.
[0008]
Therefore, the present invention is based on the knowledge of the inventor of the present invention, and even if it is continuous like a film or a sheet, the unwinding roll and the winding roll are provided outside the chamber so as to pass through the small vacuum chamber. However, the technical challenge is to enable film formation.
[0009]
[Means for Solving the Problems]
In order to solve these problems, the invention according to claim 1 inserts a film-like or sheet-like workpiece between electrodes for film formation disposed in a vacuum chamber, and supplies a raw material gas between the electrodes. And a plasma forming apparatus for continuously forming a diamond-like carbon film on the surface of the object to be processed, wherein the object to be processed before film formation is introduced from the inlet into the vacuum chamber. A conveyance line for continuously running the object to be processed toward an outlet for carrying out the object to be processed is formed, and the electrode for film formation includes a guide roller combined electrode for winding the object to be processed along the conveyance line, It consists of a substantially concentric arcuate counter electrode formed facing the portion around which the object to be processed of the electrode serving as a roller is wound, and the inlet and the outlet are formed in the shape of a thin nozzle in the cross section and formed in the intermediate throat portion thereof The Is formed by causing sprayed a sealing gas from the scan injection holes toward the outside of the chamber to the injection seal to be discharged to the outside along the air in the chamber on both sides of the object, the vacuum chamber is the degree of vacuum The pressure adjusting means for maintaining the pressure at 0.8-100 Pa is provided.
[0010]
According to the film forming apparatus of the first aspect, for example, when a diamond-like carbon film is formed on a roll film, a concentric arc-shaped electrode is arranged opposite to the guide roller combined electrode around which the film introduced into the vacuum chamber is wound. Therefore, when the film is wound around the roller electrode, the plasma is generated between the electrodes, and a diamond-like carbon film is formed on the surface facing the arc-shaped electrode.
At this time, since the unwinding roll which wound the film before film forming, and the winding roll which winds up the film after film forming can be formed out of a vacuum chamber, a vacuum chamber can be reduced in size.
In addition, the vacuum chamber is maintained at a low vacuum, and the air in the chamber is discharged without inflow of outside air by the injection seal formed at the inlet and outlet thereof, so that a predetermined degree of vacuum can be maintained, Continuous processing of the DLC coating became possible.
[0011]
Further, as in the invention of claim 2, two pairs of film-forming electrodes for individually forming diamond-like carbon films on the front side and the back side of the film are provided along the film conveyance line formed in the vacuum chamber. For example, diamond-like carbon can be formed on both sides of the film simply by passing between the electrodes.
[0012]
Furthermore, as in the invention of claim 3, since the film forming surface of the film is cleaned cleanly by plasma processing in the hydrogen atmosphere along the transfer line on the inlet side, the high vacuum is maintained. Or treating the surface with argon gas.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory view showing an example of a film forming apparatus according to the present invention.
[0014]
The film forming apparatus 21 of this example is used for forming a diamond-like carbon film on the surface of an object to be processed that is continuously conveyed like a film or a sheet.
The film forming apparatus 21 introduces a plastic film (object to be processed) 23 having a low heat resistance temperature unwound from the unwinding roll 22A into the vacuum chamber 24, and continuously formed diamond-like carbon films on both the front and back surfaces. Thereafter, the film is wound around a take-up roll 22B disposed outside the vacuum chamber 24, and a transport line 25 for continuously running the film 23 from the inlet 24in to the outlet 24out of the vacuum chamber 24 is formed. ing.
[0015]
In the vacuum chamber 24, two sets of film-forming electrodes 26A and 26B for individually forming diamond-like carbon films on both the front and back surfaces of the film 23 are disposed.
Each of the film-forming electrodes 26A and 26B has a substantially concentric arc shape formed so as to be opposed to a guide-roller electrode 27 around which the film 23 is wound along the transport line 25 and a portion of the roller-use electrode 27 around which the film 23 is wound. Counter electrode 28.
[0016]
Further, each of the film forming electrodes 26A and 26B is arranged so that the respective guide roller combined electrodes 27 are wound around the front side and the back side of the film 23, and are formed so as to rotate as the film 23 travels. ing.
The film 23 is wound around each guide roller electrode 27 and the conveying line 25 is bent in the vacuum chamber 24. Moreover, each guide roller electrode 27 also serves as a guide roller and an electrode. There is no need to provide a separate electrode along the transfer line 25, and the vacuum chamber 24 is thereby downsized.
[0017]
The guide roller combined electrode 27 and the counter electrode 28 are formed in a hollow shape, and cooling water is circulated and supplied to the inside thereof. The back surfaces of the opposing surfaces are covered with insulating covers 27a and 28a such as Teflon.
The guide roller combined electrode 27 is connected to the high frequency power supply device 30 via the matching circuit 29, and the counter electrode 28 is grounded.
[0018]
The vacuum chamber 24 is connected to a vacuum pump (pressure adjusting means) 31 for setting the degree of vacuum to 0.8 to 100 Pa, preferably 1.0 to 50 Pa, and supplies a raw material gas into the chamber 24. A tank 33C filled with a carbon-based gas such as methane gas and a tank 33H filled with hydrogen gas are vacuum-connected via a flow rate control device 34 for controlling the mixing ratio and overall flow rate of each gas. It is connected to the chamber 24.
[0019]
Furthermore, an injection seal 35 is formed at the inlet 24in and the outlet 24out, and the entry of outside air from the inlet 24in and the outlet 24out is reliably prevented.
[0020]
The injection seal 35 has an inlet 24in and an outlet 24out that are formed in a thin nozzle shape in cross section. The injection seal 35 is for sealing from the inside to the outside of the vacuum chamber 24 along both surfaces of the film 23 above and below the throat portion 36. A gas injection hole 37 for blowing gas is formed. The sealing gas may be any gas, whether hydrogen or air.
[0021]
If the gas for sealing is blown out from the gas injection hole 37, the air in the chamber 24 is sucked into the throat portion 36 due to the ejector effect of the medium and small nozzles, so that the outside air flows into the chamber 24. It is not sucked in.
[0022]
In addition, hydrogen gas supply means 38 is arranged inside the inlet 24in and outlet 24out of the vacuum chamber 24 so that the vicinity thereof is in a hydrogen atmosphere, and some ambient air flows from the inlet 24in and outlet 24out as the film 23 travels. Even if it penetrates, the diamond-like carbon film is not adversely affected.
[0023]
Further, a pretreatment device 41 for cleaning the film surface by plasma treatment in a hydrogen atmosphere is formed inside the inlet 24in.
This pretreatment device 41 is composed of two sets of roller electrodes 44A and 44B provided with metal rollers 42 and 43 that rotate in contact with both the front and back surfaces of the film 23, and one roller 42 that contacts one surface of the film 2 is matched. The other roller 43 connected to the high frequency power supply 46 through the circuit 45 and contacting the opposite surface is grounded.
[0024]
Then, the rollers 42 and 42 connected to the high frequency power source 46 are formed so as to contact the front side and the back side of the film 23, respectively, and a discharge is caused between the rollers 42 and 43 sandwiching the film 23, so that the film 23 Both sides can be cleaned.
[0025]
The above is one configuration example of the present invention, and the operation thereof will be described next.
According to this film forming apparatus 21, first, the plastic film 23 unwound from the unwinding roll 22A is set along the transport line 25, and its starting end is wound around the winding roll 2B.
And while starting the vacuum pump 31, the gas for sealing is injected from the gas injection hole 37 of the injection seal 35 formed in inlet 24in and outlet 24out, and the inside of the vacuum chamber 24 is 0.8-100Pa, Preferably 1- A high frequency is applied to the pretreatment device 41 and the film forming electrodes 26A and 26B while maintaining the pressure at 50 Pa and winding the film 23 at a predetermined speed by the winding roll 22B.
[0026]
As a result, the film 23 sent into the vacuum chamber 24 is first cleaned by the pretreatment device 21 by plasma treatment on the front and back surfaces in a hydrogen atmosphere.
Next, a diamond-like carbon film is formed on the lower surface side of the film 23 when passing through the film-forming electrode 26A, and on the upper surface side of the film 23 when passing through the film-forming electrode 26B.
[0027]
According to the inventor's experiment, a high frequency of 200 to 1000 W is applied, and the methane gas concentration (CH ₄ / H ₂ ) is 150 to 200% by volume flow rate ratio from the raw material gas supply means 32, and the total flow rate is 5 to 10 cc / min. When the film 23 was formed at a winding speed of 1 to 44 cm / sec, it could be formed with a film thickness of 500 to 700 mm on one side.
When the length of the portion where the film 23 is wound around the guide roller electrode 27 is about 10 cm, the high frequency application time is about 0.23 to 10 seconds.
[0028]
Thus, after pre-treatment in a hydrogen atmosphere, a diamond-like carbon film was formed, and a good quality film could be formed.
At this time, since the inside of the vacuum chamber 24 is maintained at a relatively low vacuum, even if the inlet 24in and the outlet 24out are opened, the intrusion of outside air is surely prevented by the injection seal 35.
[0029]
Accordingly, the film 23 unwound from the unwinding roll 22A is introduced into the vacuum chamber 24 while being continuously supplied to form a diamond-like carbon film on the surface thereof, and then the winding roll 22B outside the vacuum chamber 24 is formed. Therefore, the vacuum chamber 24 itself can be downsized and its pressure resistance is low.
[0030]
Moreover, when the degree of vacuum is 0.8 to 100 Pa, the plasma temperature can be suppressed to 20 to 80 ° C., and when the degree of vacuum is 1 to 50 Pa, the plasma temperature can be suppressed to 20 to 50 ° C. When a diamond-like carbon film is formed on an object, the object to be processed is not deformed or deteriorated.
[0031]
【The invention's effect】
As described above, according to the present invention, since a film can be formed at a relatively low vacuum without using a high vacuum, a diamond-like carbon film can be formed in a vacuum chamber having a relatively low strength. It is possible to simplify the equipment.
[0032]
Furthermore, since the film can be formed in a low vacuum, even if the inlet and outlet are formed in the vacuum chamber, it suffices to provide an injection seal there, and the film is formed into a continuous film or sheet. In this case, the unwinding roll and the winding roll can be provided outside the chamber, and the DLC film forming process can be performed while running in the chamber.
In addition, since the electrode for film formation also serves as a guide roller, there is no need to provide a separate electrode, and the chamber can be downsized.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of a film forming apparatus according to the present invention.
[Explanation of symbols]
23 ……… Plastic film (object to be treated)
21 ... …… Film forming device 24 ... …… Vacuum chamber 24in …… Inlet 24out …… Outlet 25 ……… Transfer line 26A, 26B… Film forming electrode 27 ……… Guide roller combined electrode 28 ……… Electrode 30 …… ... Power supply 31 ......... Vacuum pump (pressure adjusting means)
32... Raw material gas supply means 35... Injection seal 41.

Claims (3)

A film-like or sheet-like object (23) is inserted between the electrodes for film formation arranged in the vacuum chamber, and a raw material gas is supplied between the electrodes and plasma is generated to form a surface on the object to be processed. A film forming apparatus for continuously forming a diamond-like carbon film,
The workpiece (23) from the inlet (24in) for introducing the workpiece (23) before film formation into the vacuum chamber (24) toward the outlet (24out) for carrying out the workpiece (23) after deposition. ) Is continuously formed, a transfer line (25) is formed,
The electrode for film forming winds the electrode (27) serving also as a guide roller for winding the object (23) along the conveying line (25), and the object (23) for the roller electrode (27). Consists of a substantially concentric arc-shaped counter electrode (28) formed facing the hung portion,
The inlet (24in) and the outlet (24out) are formed in a thin nozzle shape in cross section, and sealed from the gas injection hole (37) formed in the intermediate throat portion (36) toward the outside of the chamber (24). Formed in the injection seal (35) that discharges the air in the chamber to the outside along both sides of the object to be processed by blowing out the working gas,
A film forming apparatus comprising pressure adjusting means (31) for maintaining the degree of vacuum in the vacuum chamber (24) at 0.8 to 100 Pa.   A diamond-like carbon film is individually formed on the front side and the back side of (23) of the workpiece along the transfer line (25) of the film-like or sheet-like workpiece (23) formed in the vacuum chamber (24). The film-forming apparatus according to claim 1, wherein two sets of film-forming electrodes (26A, 26B) are formed.   A film film or sheet processed object (23) is formed by plasma processing in the hydrogen atmosphere along the transfer line (25) formed in the vacuum chamber (24) on the inlet (24in) side. The film forming apparatus according to claim 1 or 2, wherein a pretreatment device (41) for cleaning the film forming surface is formed.

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