JP5045395B2 - Deposition equipment - Google Patents

Description

  The present invention relates to a film forming apparatus for forming a film by vapor deposition under vacuum, and more particularly to a film forming apparatus suitable for coating an optical element such as a plastic lens.

As a vacuum film forming apparatus, a vacuum chamber containing a substrate and a deposition source, an ionized gas generating means for generating ionized gas, and an ionized gas supply means that is a pipe or valve provided between the vacuum chamber and the ionized gas generating means, (For example, refer to Patent Document 1). In this vacuum film forming apparatus, the ionization gas is introduced into the vacuum chamber at the time of depressurization before film formation, thereby removing the charge from the substrate and removing dust from the substrate surface.
Japanese Patent Laid-Open No. 2001-247955

  However, in the vacuum film forming apparatus as described above, when the vacuum chamber is opened to the atmosphere after film formation and the substrate after film formation is taken out, the ionized gas cannot be introduced into the vacuum chamber, and dust adheres. there is a possibility. In particular, in the coating of plastic lenses, vacuum deposition is often performed with the lens heated, and the substrate (lens) is still at a high temperature when the series of film formation is completed and the atmosphere including the slow leak is released, and fine dust is generated. Easy to stick after adhering. Therefore, it has been found that it is not sufficient to remove static electricity before film formation, and fine dust adheres to the lens surface, that is, the coat, resulting in a defective product. Such adhesion of fine dust after film formation is caused when dust or the like adhering to the wall of the vacuum chamber is attracted onto the charged lens coat as the atmosphere is introduced when the vacuum chamber is opened to the atmosphere. Conceivable.

  Therefore, an object of the present invention is to provide a film forming apparatus that can prevent fine dust from adhering to the surface of a film forming target such as a lens after the film forming to become a defective product.

In order to solve the above-described problems, a film forming apparatus according to the present invention includes (a) a deposition source for film formation, (b) a holder for holding a workpiece to be formed, (c) a deposition source and a holder. preparative a vacuum container for storing and a decompressor for decompressing (d) is a vacuum container, disposed within (e) vacuum vessel, and a ionization unit for ionizing the ambient air that is introduced into the vacuum chamber, the ionization part Is a path of air from the air introduction hole of the vacuum vessel to the work held by the holder, and is disposed so as to cover the air introduction hole, and the work is a plastic lens coated by film formation. is there.

In the film forming apparatus, the ionization unit is disposed in the vacuum container and ionizes the outside air introduced into the vacuum container. Therefore, when the inside of the vacuum container is opened to the atmosphere, the atmosphere introduced into the vacuum container It is possible to prevent the workpiece from being charged, and it is possible to prevent unintended particles such as dust adhering to the inner wall of the vacuum container from being attracted to the workpiece after film formation and adhering to the film. That is, it is possible to prevent a defect from occurring when the workpiece after film formation is taken out.
In the film forming apparatus, the ionization unit is disposed on the air path from the air introduction hole of the vacuum vessel to the work held by the holder so as to cover the air introduction hole. Thereby, since the air introduced from the air introduction hole can be efficiently ionized before reaching the workpiece, it is possible to more reliably eliminate the charge of the workpiece and prevent the particles from adhering.
In the film forming apparatus, the workpiece is a plastic lens that is coated by film formation. Thereby, generation | occurrence | production of a defect can be suppressed, for example about antireflection film and other various coatings formed in the surface of a lens.

  In another aspect of the present invention, the leak portion that enables the introduction of outside air into the vacuum vessel through the air introduction hole is further provided with a leak valve, and the ionization portion is in proximity to the air introduction hole that communicates with the leak valve. Has been placed. In this case, the outside air from the leak valve provided in the leak portion can be directly ionized to a desired degree and then diffused into the vacuum vessel.

  According to still another aspect of the present invention, the apparatus further includes a heating device that heats a workpiece disposed in the vacuum vessel and fixed to the holder. In this case, the film quality and adhesion can be ensured by heating the workpiece with a heating device, but the chargeability of the air when the inside of the vacuum vessel is opened to the atmosphere also tends to increase. It will be more effective.

  Hereinafter, a film forming apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a side view conceptually illustrating the structure of the film forming apparatus of the present embodiment. The film forming apparatus 100 includes a vapor deposition source 10 for film formation, a holder 20 that holds a plurality of workpieces W, a heating device 30 that heats the workpieces W, and a vacuum container 40 that stores the vapor deposition source 10, the holder 20, and the like. And a decompression device 50 that decompresses the inside of the vacuum vessel 40, a slow leak portion 60 that gently introduces the outside air AR into the vacuum vessel 40, and an outside air AR that is disposed inside the vacuum vessel 40 and is introduced from the outside. An ionization unit 70. In addition, the workpiece | work W used as the object of the film-forming by this film-forming apparatus 100 is a small plastic lens formed by injection molding, for example, is used as an objective lens of an optical pick-up apparatus.

  The deposition source 10 enables vacuum deposition of an inorganic film forming material, and includes a crucible portion 11 and an electron gun portion 12. Here, the crucible part 11 accommodates an evaporation substance for coating the surface of the workpiece W, and the electron gun part 12 makes the electron beam EB incident on the evaporation substance in the crucible part 11. Thereby, the evaporated substance in the crucible part 11 can be heated and melted by the electron beam EB, and the vapor EM of the evaporated substance can be injected upward from the crucible part 11. The number of crucible portions 11 is not limited to a single one, and a plurality of crucible portions 11 can be provided. A plurality of film forming materials can be coated on the surface of the work W, and a multilayer coating is formed on the surface of the work W by changing the film forming material can do.

  The holder 20 arranges a plurality of workpieces W above the vapor deposition source 10 in a state of facing the vapor deposition source 10. The holder 20 has an opening 21 that exposes the optical surface 91 of each workpiece W downward, as shown partially enlarged. Through this opening 21, the vapor EM from the evaporation source 10 can be incident on the optical surface 91 of the workpiece W to deposit the evaporated substance. The deposited film or thin film deposited on the optical surface 91 is, for example, an antireflection film, but may be an optical thin film having various functions such as a filter. In addition, although illustration is abbreviate | omitted, the holder 20 can change an attitude | position in the vacuum vessel 40. FIG.

  The heating device 30 includes a plurality of halogen lamps 31 disposed on the lower side of the vacuum vessel 40, and heat rays HB from the halogen lamps 31 are incident on the optical surface 91 of the workpiece W supported by the holder 20 and its periphery. The optical surface 91 and the like of the workpiece W can be heated to a desired temperature before film formation, during film formation, or after film formation. The heating device 30 can raise and lower each halogen lamp 31 in the vacuum container 40, and can adjust the distance from the halogen lamp 31 to the holder 20.

  In the internal space IS, the vacuum vessel 40 supports the vapor deposition source 10 at the bottom, supports the holder 20 at the top, and supports the heating device 30 facing the holder 20 downward. A door 41 for opening or sealing the internal space IS is provided on the side surface of the vacuum vessel 40. This door 41 is provided with a hinge and a fastener (not shown). The vacuum vessel 40 is connected to a decompression device 50 and a slow leak unit 60. Further, the vacuum container 40 supports the ionization unit 70 at a position close to the slow leak unit 60 in the internal space IS.

  The decompression device 50 includes a rotary pump 51 and an oil diffusion pump 52, and these rotary pump 51 and oil diffusion pump 52 are connected to the vacuum vessel 40 via pipes 53 and 54, a roughing valve 55, and a main valve 56. Has been. Here, the rotary pump 51 can depressurize the internal space IS of the vacuum vessel 40 to a low degree of vacuum, and the oil diffusion pump 52 can depressurize the internal space IS to a high degree of vacuum. Although not shown, the pipes 53 and 54 are also provided with a leak valve 58 for introducing the atmosphere into the internal space IS or the like. Vacuum deposition by the deposition source 10 is performed in a state where the internal space IS is decompressed to a high vacuum by the oil diffusion pump 52. The decompression device 50 does not need to be configured with the oil diffusion pump 52 or the like as described above, and can be replaced with a cryopump or the like.

  The slow leak unit 60 can introduce the outside air AR, the pipe 61 that takes in the outside air AR, the filter 62 that is provided in the pipe path and prevents the passage of particles (including dust, polymer, and the like here), and the outside air AR. Therefore, a leak valve 63 that can be freely opened and closed and an air introduction hole 64 that faces the inside of the vacuum vessel 40 are provided. When the leak valve 63 is slightly opened after film formation by vacuum deposition, the outside air AR is gradually introduced into the internal space IS of the vacuum vessel 40. As a result, it is possible to prevent a vigorous air flow from being formed in the internal space IS, so that particles such as a film forming material (evaporation mist) accumulated at the bottom of the vacuum vessel 40 rise and the optical surface 91 of the workpiece W, ie, the film surface Adhering to the top can be suppressed to some extent.

  The ionization unit 70 is disposed in the vacuum container 40 in the vicinity of the air introduction hole 64 that communicates with the leak valve 63 of the slow leak unit 60. That is, the ionization part 70 is arrange | positioned on the path | route of the introduction air LA from the air introduction hole 64 to the workpiece | work W hold | maintained at the holder 20 in internal space IS. By providing the ionization unit 70, the introduced air LA is ionized before coming into contact with the surface of the workpiece W. Thereby, since the introduction air LA is in contact with the surface of the workpiece W and neutralizes the charge, the probability that particles or the like are attracted and adhered to the surface of the workpiece W, particularly the optical surface 91, can be reduced. Therefore, even if particles such as vapor deposition mist remaining on the bottom of the vacuum vessel 40 rise with the introduction of the outside air AR by the slow leak part 60, it becomes difficult to adhere to the optical surface 91 of the workpiece W, and after the film formation It is possible to prevent film formation defects from occurring on the workpiece W. The ionization unit 70 periodically ionizes the introduced air LA alternately, for example, positive and negative. Specifically, a low-frequency corona discharge ionization device, a high-frequency corona discharge ionization device, or the like may be used. it can. The introduced air LA can also be ionized using electromagnetic waves.

  Here, the low frequency corona discharge type ionization apparatus is of a type in which, for example, corona discharge is performed at a commercial frequency, and + ions and − ions are blown by a fan. Such a charge removal device portion of the ionization device can be attached to the slow leak portion 60 as the ionization portion 70. Note that the ionizer normally includes a fan for blowing air. However, in the case of the present embodiment, since the air for slow leak from the slow leak portion 60, that is, the introduced air LA has a blowing function, the vacuum vessel 40 is provided by the introduced air LA. The inside can be filled with ionized air.

  In addition, the ionizer for high-frequency corona discharge is a type in which corona discharge is performed at a frequency of, for example, several tens of Hz, and fine + ions and − ions are blown. There are many things. Such a static elimination device portion of the ionization device can be attached to the slow leak portion 60 as the ionization portion 70. Also in this case, since the introduced air LA from the slow leak portion 60 has a blowing function, the vacuum vessel 40 can be filled with ionized air by the introduced air LA.

  In addition, when the workpiece | work W is heated to about 40-100 degreeC, for example at the time of film-forming, and the introduction air LA is not ionized, it is thought that frictional electrification tends to arise between the introduction air LA. . For this reason, when particles such as vapor deposition mist rise by the air flow formed by the introduced air LA by the slow leak portion 60 or dust flows in along with the external air flowing in after the door 41 of the vacuum vessel 40 is opened, Particles are attracted and attached onto the deposited film on the optical surface 91 of W. In particular, when particles adhere to the optical surface 91 of the workpiece W immediately after film formation, a phenomenon occurs in which such particles are weakly welded and it is difficult to remove the particles. Specifically, the phenomenon as described above will be described. For example, when an outside air AR having a temperature of 25 ° C. and a humidity of 50% is introduced into the internal space IS and rapidly heated to, for example, a temperature of 80 ° C. as the introduction air LA, the humidity is several. %. The introduced air LA thus dried at low humidity is considered to easily charge the surface of the workpiece W, and particles adhering to the electrostatic surface 91 on the relatively high-temperature optical surface 91 are charged with static electricity and heat. Due to both effects, it adheres firmly and becomes poor in appearance. Increasing the amount of adhesion also affects the optical performance. Therefore, ionization of the introduced air LA as in the present embodiment can effectively prevent particles from adhering to the optical surface 91 of the workpiece W and causing contamination. Here, if the work W is sufficiently cooled in a state where the degree of vacuum in the vacuum container 40 is kept sufficiently high, it is considered that the effect of charging by the dry air as described above can be reduced, but the time required for cooling is reduced. Increasing the length generally decreases the throughput of the film forming process.

  FIG. 2 is a block diagram illustrating a control system of the film forming apparatus 100 of FIG. Note that when the film forming apparatus 100 is mainly operated manually, a control system described below is not necessary.

  The control system of the film forming apparatus 100 includes a deposition source driving unit 82 that operates the deposition source 10, a heating device driving unit 83 that operates the heating device 30, a decompression device driving unit 84 that operates the decompression device 50, and an ionization unit. 70, an ionization unit driving unit 85 that operates 70, a valve driving unit 86 that operates the leak valve 63 of the slow leak unit 60, the decompression device 50, the valves 55, 56, and the like, and a thermometer (not shown), a vacuum gauge, and the like. The sensor drive part 87, the holder rotation drive part 88 which rotates the holder 20 within a horizontal surface, and the control part 81 which controls these operation | movement centrally are provided.

  FIG. 3 is a flowchart for explaining the operation of the film forming apparatus 100 shown in FIGS. In advance, the door 41 is closed in a state where a plurality of workpieces W are set on the holder 20 in the vacuum vessel 40 and the evaporation substance is set in the vapor deposition source 10. First, the decompression device 50 is operated under the control of the control unit 81 to decompress the internal space IS of the vacuum vessel 40 to a high vacuum (step S12). Then, after the pressure in the vacuum container 40 is reduced or in parallel, the heating device 30 is operated under the control of the control unit 81 to raise the temperature of the workpiece W to a temperature required for film formation (step S13). Next, the vapor deposition source 10 is operated under the control of the control unit 81 to coat the surface of the workpiece W with the film forming material (step S14). At this time, by rotating the holder 20 via the holder rotation driving unit 88, the position of the workpiece W on the holder 20 can be changed during the film formation, and a large number of workpieces W can be formed uniformly. Next, by stopping the operation of the vapor deposition source 10 and the heating device 30 under the control of the control unit 81, the vapor deposition of the film forming material is stopped and the work W is gradually cooled (step S15). Thereafter, when the workpiece W has cooled to some extent, the operation of the slow leak unit 60 is started under the control of the control unit 81, and the inside of the vacuum vessel 40 is gradually returned to the external pressure (step S16). At this time, the ionization unit 70 is operated under the control of the control unit 81, and the introduced air LA is ionized before coming into contact with the surface of the workpiece W. As a result, it is possible to suppress a phenomenon in which particles or the like that rise while preventing charging of the surface of the workpiece W adhere to the surface of the workpiece W, that is, the optical surface 91. In addition, another leak valve (not shown) attached to the decompression device 50 can be operated from the middle of the operation of the slow leak unit 60. In this case as well, the surface of the workpiece W is charged by the introduced air LA that has passed through the ionization unit 70. It can be suppressed below a certain level. Finally, when it is detected that the atmospheric pressure in the vacuum container 40 has reached the external atmospheric pressure, the control unit 81 displays this to the operator, thereby permitting the opening of the door 41 of the vacuum container 40 (step S17).

  As is clear from the above description, according to the film forming apparatus 100 of the present embodiment, the ionization unit 70 is arranged in the vacuum vessel 40 and ionizes the introduced air LA introduced into the vacuum vessel 40. When the inside of the vacuum vessel 40 is opened to the atmosphere, the workpiece W can be prevented from being charged by the introduced air LA, and unintended particles such as dust adhering to the inner wall of the vacuum vessel 40 are attracted to the workpiece W after film formation. It is possible to prevent adhesion on the deposited film. That is, it is possible to prevent a product defect from occurring when taking out the workpiece W after film formation.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above embodiment, the ionization unit 70 is disposed adjacent to the air introduction hole 64 of the slow leak unit 60, but can be disposed away from the air introduction hole 64. That is, if the ionization unit 70 is arranged on the path until the introduced air LA reaches the optical surface 91 on the film formation side of the workpiece W, the probability that particles or the like adhere to the deposited film due to ionization of the introduced air LA is reduced. can do. Note that the ionization unit 70 may be installed in the vacuum vessel 40 at a plurality of locations without being limited to one location.

  Further, in the above embodiment, the inside of the vacuum vessel 40 is not charged during decompression before film formation, but as shown in FIG. 1, an ionized gas generator 93 is provided, and the ionized gas generated thereby is supplied to the vacuum vessel. By introducing into 40, the work W can be neutralized at the time of decompression before film formation, and dust can be removed from the surface of the work W.

  In the above-described embodiment, the workpiece W is a plastic lens. However, the workpiece W is not limited to a lens, and can be various optical elements. It can also be an inorganic material.

  Moreover, in the said embodiment, although the ionization part 70 was provided accompanying the slow leak part 60, the ionization part 70 can also be provided accompanying a normal leak part.

  Although omitted in the above embodiment, an opening / closing shutter that prevents vapor EM or the like from entering the surface of the holder 20 or the workpiece W at a necessary timing can be provided between the vapor deposition source 10 and the holder 20.

  Moreover, in the said embodiment, although the vapor deposition source 10 is heated with the electron beam EB, the vapor deposition source 10 can also be heated with another heating method.

It is a side view which illustrates notionally the structure of the film-forming apparatus of this embodiment. It is a block diagram explaining the control system of the film-forming apparatus of FIG. 2 is a flowchart for explaining the operation of the film forming apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Deposition source, 11 ... Crucible part, 20 ... Holder, 21 ... Opening, 30 ... Heating device, 31 ... Halogen lamp, 40 ... Vacuum container, 50 ... Decompression device, 51 ... Rotary pump, 52 ... Oil diffusion pump, 60 DESCRIPTION OF SYMBOLS ... Slow leak part 61 ... Piping 62 ... Filter 63 ... Leak valve 64 ... Air introduction hole 70 ... Ionization part 81 ... Control part 82 ... Deposition source drive part 83 ... Heating device drive part 84 ... Pressure reducing device drive unit, 85 ... Ionization unit drive unit, 100 ... Film forming device, EB ... Electron beam, EM ... Steam, IS ... Internal space, LA ... Introducing air, W ... Workpiece

Claims (3)

A deposition source for film formation;
A holder for holding a workpiece to be deposited;
A vacuum container for housing the vapor deposition source and the holder;
A decompression device for decompressing the inside of the vacuum vessel;
An ionization unit disposed in the vacuum vessel and ionizing outside air introduced into the vacuum vessel;
Equipped with a,
The ionization part is disposed on the air path from the air introduction hole of the vacuum vessel to the work held by the holder, and is disposed adjacent to the air introduction hole,
The film forming apparatus , wherein the workpiece is a plastic lens coated by film formation. The leak portion that allows outside air to be introduced into the vacuum vessel through the air introduction hole further includes a leak valve,
The film forming apparatus according to claim 1 , wherein the ionization unit is disposed in proximity to the air introduction hole communicating with the leak valve. 3. The film forming apparatus according to claim 1 , further comprising a heating device configured to heat a workpiece disposed in the vacuum vessel and fixed to the holder.

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