JP3237399B2 - Vacuum deposition equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vacuum deposition of a flexible plastic film having various functions usable in fields such as food packaging, pharmaceutical packaging, electronic equipment parts packaging, tobacco packaging, photoengraving, and photosensitive photographic materials. The present invention relates to a vacuum deposition apparatus suitably used for processing.

[0002]

2. Description of the Related Art In recent years, a metal or metal oxide is coated on the surface of a flexible plastic film by a vacuum vapor deposition method to provide decorativeness, gas barrier properties, chemical resistance, wetting properties, magnetic properties, electrical conductivity, dimensional stability, etc. It has added functionality and has been used in fields such as food packaging, pharmaceutical packaging, electronic device parts packaging, tobacco packaging, photoengraving and photosensitive photographic materials. In particular, aluminum vapor-deposited films have been widely used for decoration and packaging applications. In recent years, research and development of silicon oxide vapor deposition film has been actively conducted as a transparent high barrier material with low environmental pollution, and the demand for the development of metal oxide vapor deposition technology is expected to be widespread. It is getting stronger.

[0003] In response to the expansion of these uses, mass production and reduction of processing costs have become necessary. For this reason, it is practical to shorten the processing time by increasing the processing speed by raising the evaporation temperature, increase the area that can be produced in one processing step by extending the width of the film to be mounted, and extend the processing length. And the deposition apparatus has become larger. Above all, in order to increase the processing speed, vacuum evaporation apparatuses have been increasing in which the evaporation amount and the evaporation rate are increased by increasing the size of the evaporation source and increasing the evaporation temperature. However, the increase in the size of the evaporation source and the increase in the deposition temperature both increase the amount of heat generated from the evaporation source, and furthermore, since the evaporation source does not have a structure for shielding and keeping the temperature of the evaporation source, the evaporation source is not used. In addition to low thermal efficiency, there is a problem that quality deterioration such as damage due to thermal deformation or thermal fatigue of parts around the evaporation source, wrinkling due to thermal deterioration of the base film, reduction in barrier performance of the deposition film, reduction in tear strength, etc. There was a point.

Further, in the case of vapor deposition of a metal such as aluminum, chromium, copper, and silver, a heat ray from an evaporation source is reflected by a metal such as aluminum which is a vapor deposition film. When a film is subjected to vapor deposition, the vapor deposited film absorbs heat rays from the evaporation source together with the base film without reflecting it, and thus the problem of deterioration in the quality of the vapor deposited film due to thermal deterioration of the base film is particularly large.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the thermal efficiency of a large-sized and / or high-temperature evaporation source for high-speed production, while avoiding damage to peripheral parts and deterioration of the quality of a deposited film. It is to provide a device.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum evaporation apparatus in which an evaporation source is surrounded by a box-shaped evaporation source heat shielding structure, wherein the evaporation source heat shielding structure is provided from the outside. To the evaporation source, it consists of a metal plate cooled by a water-cooled pipe, a graphite fiber compression molded plate, a graphite plate or a boron nitride molded plate, and
It has an opening inclined at an angle of 5 degrees or more and an evaporation material is evaporated and an opening for supplying the evaporation material, and the temperature at the tip of the opening at which the evaporation material is evaporated is equal to or higher than the evaporation temperature of the evaporation particles. This can be achieved by a characteristic vacuum deposition apparatus.

The method of heating the evaporation source can be selected without particular limitation from known methods such as a resistance heating method, a high-frequency induction heating method, and an electron beam heating method. Although there is no particular limitation on whether or not the evaporation raw material is of a continuous supply type, JP-A-1-252768 and JP-A-2-2-268.
JP-A-77774 discloses an evaporation source having an evaporation material continuous supply mechanism using a resistance heating method in which the area of a portion where evaporation material does not evaporate is relatively large when the evaporation source is viewed from above. Particularly excellent effects are exhibited when a transparent vapor-deposited film is formed using a vacuum vapor-deposition device surrounded by a source heat-shielding structure. FIG. 1 shows a schematic diagram thereof. The evaporation source heat shielding structure surrounding the evaporation source is composed of a metal plate / intermediate heat insulation layer / inside heat insulation layer from the outside to the evaporation source, and specifically, a metal plate / graphite fiber cooled by a water cooling pipe, respectively. It consists of a compression plate / graphite plate or boron nitride plate.

Since the outer surface of the evaporation source heat shielding structure needs to be as low as possible in temperature to enhance the heat shielding effect, it is preferable to use a metal plate to which a water cooling pipe for cooling is added. As the metal material, most metals can be used if only heat resistance, workability, and weight are considered, but in order to efficiently cool with a water-cooled pipe, solder that can be connected with good heat conduction, Copper, iron, stainless steel, etc., which can be easily welded by silver brazing or the like, are suitable. As the material of the intermediate heat insulating layer needs to have a high heat retaining effect, a material that has a high heat insulating effect and emits a small amount of gas under high-temperature vacuum should be selected from materials that can withstand the high temperature of the evaporation source. There must be. Graphite fibers are suitable for the heat insulating layer from the viewpoints of heat insulation, heat resistance, released gas, and the like, and among them, the one in which graphite fibers are compression-molded into a plate shape is most suitable.

[0009] The inner heat insulating layer of the evaporation source heat shielding structure has a high temperature (depending on the evaporation raw material and evaporation conditions, etc., usually has a temperature of 130 ° C.).
(0 ° C or higher).
It is necessary to have heat resistance higher than that of the intermediate heat insulating layer, and in particular, it must be made of a material that does not cause breakage due to rapid heating and rapid cooling during heating and cooling. Further, since the raw material is directly exposed to the vaporized raw material gas, some vaporized raw materials require corrosion resistance to the gas (for example, when an oxide such as silicon oxide is deposited, oxidation consumption is small). As the material of the inner heat insulating layer of the evaporation source heat-shielding structure, a material that emits less gas under a high-temperature vacuum must be selected from materials satisfying these conditions. Taking into account heat resistance, corrosion resistance, and gas emission characteristics, as well as the price, workability, and strength of the material, an isotropic graphite plate (graphite isotropic compression molded plate) is most suitable. However, when used in a place where electrical insulation is required, a boron nitride molded body is most suitable. In this case, if an insulator such as aluminum oxide or magnesium oxide is used, even if a high-purity product is used, breakage is caused by repeating the cooling / heating cycle.

In the heat-shielding structure for the evaporation source, the shape of the upper opening, which is a hole for evaporating the evaporated material, and the temperature at the tip of the opening are particularly important. The upper opening of the evaporation source heat shield structure must be designed so as not to obstruct the flight path of the evaporated particles in order to ensure the uniformity of the quality of the deposited film. Specifically, 1. The top opening should be positioned at 4
Incline at an angle of 5 degrees or more. 2. The temperature of the tip of the upper opening closest to the evaporation source is set to be equal to or higher than the evaporation temperature of the evaporation particles so that the evaporation particles do not adhere and deposit. The temperature of the tip of the upper opening may be equal to or higher than the evaporation temperature of the evaporating particles using a heater, or may be equal to or higher than the evaporation temperature of the evaporating particles by contacting the upper end of the upper opening with an evaporation source and conducting heat. In order to minimize the energy loss of the evaporation source due to heat conduction, it is preferable that the area where the evaporation source and the upper heat shield structure come into contact is as small as possible. If not designed as described above, as shown in FIG. 6 and FIG. 7, evaporated particles collide and adhere to the water-cooled metal plate of the opening or the tip of the opening, and further evaporated matter adheres thereon. This causes the growth of deposits. The grown deposits impede the flight of the evaporated particles, thereby hindering uniform deposition, and as a result, the uniformity of the quality of the deposited film cannot be maintained.

The total thickness of the portion of the evaporation source heat shielding structure that covers the upper portion of the evaporation source is determined from the viewpoint of maintaining the flight path of the evaporation particles, determining the distance between the evaporation source and the cooling roll from the viewpoints of deposition efficiency, physical properties of the deposited film, and the like. Since it is necessary to make the evaporation source and the deposition film as close as possible, it is preferable to make the evaporation source as thin as possible. In addition, the portion of the evaporation source heat shielding structure that covers the upper portion of the evaporation source needs to be removed and lifted during maintenance of the evaporation source, so that it is preferable that the portion be as light as possible. 3 and 4 are cross-sectional views of the periphery of the evaporation source when the evaporation source of the resistance heating type having the mechanism for continuously supplying the aluminum wire is surrounded by the evaporation source heat shielding structure of the present invention. In this case, the tip of the upper opening of the evaporation source heat shielding structure is heated by a method using heat conduction from the evaporation source. Note that the tip of the upper opening of the evaporation source heat shielding structure can be heated by a heating means such as a heater.

JP-A-1-252768 and JP-A-2-
No. 2,777,774, a sublimation method using a resistance heating type evaporation source having an evaporation material continuous supply / discharge mechanism having a relatively large area of a portion where the evaporation material does not evaporate when the evaporation source is viewed from above. When the evaporation source is vacuum-deposited, the area of the high-temperature portion of the evaporation source is increased, and the amount of heat received by the evaporation source heat shielding structure naturally increases. In this case, in order to reduce the heat load as much as possible, in addition to installing the evaporation source heat shielding structure as described above, as shown in FIGS. 1 and 2, a heater (FIGS. 1 and 2A) and a crucible are used. (FIG. 2-B), a heat-shielding molded body such as a boron nitride molded body, an aluminum oxide molded body, or a magnesium oxide molded body can be closely attached to an outside of an evaporation source such as a boat. As a result, it is possible to obtain a heat shielding effect, a heat retaining effect, and an effect of reducing corrosion to gas such as oxidative consumption of the evaporation source. In particular, a boron nitride molded article is preferably used because of its excellent heat resistance. When manufacturing a transparent evaporated film, there is no reflection of heat rays,
The deposited film absorbs heat rays from the evaporation source together with the base film, and increases the heat load on the base film.
As shown in FIG. 1 and FIG. 2, the effect of preventing the deterioration of the quality of the vapor-deposited film is great by bringing the evaporation source heat shielding structure into close contact with the evaporation source.

[0013] The evaporation source may be any material that becomes a transparent vapor deposition film when it becomes a vapor deposition film, and specifically includes silicon oxide, aluminum oxide, magnesium oxide, titanium oxide, indium oxide, and tin. Compounds such as oxides can be used alone or as a mixture. In the case of using a reactive evaporation method in which evaporation is performed while reacting, silicon, aluminum, magnesium, titanium, indium, tin, or the like can be used.

[0014]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation of the vapor deposition film obtained in the examples and observation of the heat shield structure,
The procedure was as follows. Oxygen barrier property: ASTM D
3985 compliant, US Modern Controls OX
Measure the oxygen gas permeability using TRAN-TWIN,
The measured value was represented by an average value and a maximum value-minimum value. Observation of deposits on the heat shield structure: 50 minutes after the start of vacuum vapor deposition, the presence or absence of deposits on the upper opening of the heat shield structure was visually observed. Observation of breakage of the heat shield molded body adhered to the evaporation source: After vacuum deposition, the heat shield molded body adhered to the evaporation source was disassembled and visually inspected for damage. Observation of appearance of deposited film: The appearance of the obtained deposited film was visually evaluated.

[First Embodiment] As shown in FIG.
Vacuum evaporation was performed using a vacuum evaporation apparatus provided with an evaporation source heat shield structure in an evaporation source described in Japanese Patent Application Publication No. 252768 (total area as viewed from above: 270 cm ² ). As an evaporation raw material, an equimolar mixture of silicon and silicon dioxide (amorphous) was used.
A molded product compression-molded into a column having a diameter of 40 mm and a height of 35 mm was used. The molded product was continuously supplied at a supply speed of 5 mm / min from a supply port of a continuous supply and discharge mechanism of the evaporated raw material. The evaporation source is heated to 1350 ° C. by resistance heating under a vacuum of 1 × 10 ⁻⁴ torr, and has a thickness of 12 μm and a width of 1500.
A silicon oxide was vacuum-deposited on a biaxially stretched polyethylene terephthalate film having a thickness of 2 mm. The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 150 kJ / sec.
Under these conditions, the processing speed was 50 m / min, and vacuum deposition was performed for 1 hour. When the thickness of the deposited film was measured using a quartz crystal film thickness monitor, it was about 1000 Å. Further, the temperature of the tip of the upper opening of the evaporation source heat shielding structure was measured at 1280 ° C. using an R thermocouple, and no evaporant adhered to the tip of the upper opening.

[Embodiment 2] As shown in FIG. 3 and FIG.
Using a vacuum evaporation system equipped with a heat shield structure on a resistance heating type evaporation source equipped with a mechanism for continuously supplying aluminum wires, the aluminum wire wound in a wire shape is continuously fed from the supply port at a supply speed of 10 mm / min. Supplied. The evaporation source was heated by resistance heating under a vacuum of 1 × 10 ⁻⁴ torr.
Heated to 00 ° C., aluminum was vacuum deposited on a 12 μm thick polyethylene terephthalate film. The calorific value of the evaporation source calculated from the total power input to the evaporation source is 120
kJ / sec. Processing speed is 100m under the same conditions
/ Minute, vacuum deposition was performed for 1 hour. When the thickness of the deposited film was measured using a quartz crystal film thickness monitor, about 500
Angstrom. The temperature of the tip of the upper opening of the evaporation source heat shielding structure was measured using an R thermocouple. As a result, it was found to be 1320 ° C., and no evaporated material was attached to the tip of the upper opening.

Example 3 The same procedure as in Example 1 was carried out except for removing the boron nitride molded body closely adhered to the outside of the evaporation source from the evaporation source heat shielding structure used in Example 1.
The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 170 kJ / sec. The processing speed is 5 under the same conditions
Vacuum deposition was performed at 0 m / min for 1 hour. The thickness of the deposited film was measured using a quartz crystal film thickness monitor.
000 angstroms. The temperature of the tip of the upper opening of the evaporation source heat shielding structure was measured using an R thermocouple. As a result, the temperature was 1340 ° C., and no evaporated matter was attached to the tip of the upper opening.

[Embodiment 4] Among the evaporation source heat shielding structures used in Embodiment 1, the boron nitride molded body closely adhered to the outside of the evaporation source was changed to an aluminum oxide sintered body, and otherwise the same as in Embodiment 1 The same was done. The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 150 kJ / sec. Under these conditions, the processing speed was 50 m / min, and vacuum deposition was performed for 1 hour. When the thickness of the deposited film was measured using a quartz crystal film thickness monitor, it was about 1000 Å. When the temperature of the tip of the upper opening of the evaporation source heat shielding structure was measured using an R thermocouple, it was 1280 ° C.,
No evaporant adhered to the top opening tip.

Comparative Example 1 The same procedure as in Example 1 was carried out except that only the upper part of the evaporation source heat shielding structure used in Example 1 was removed. The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 200 kJ / sec. Under these conditions, the processing speed was 50 m / min, and vacuum deposition was performed for 1 hour. During processing, it was observed that the polyethylene terephthalate film suffered a heat loss phenomenon. The thickness of the deposited film was measured using a quartz crystal film thickness monitor.
000 angstroms.

[Comparative Example 2] The upper opening of the evaporation source heat shielding structure used in Example 1 was inclined at an angle of 30 degrees with respect to the vertical plane (an angle that hinders the flight of evaporated particles). Performed in the same manner as in Example 1. The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 150 kJ / sec.
Under these conditions, the processing speed was 50 m / min, and vacuum deposition was performed for 1 hour. When the thickness of the deposited film was measured using a quartz crystal film thickness monitor, it was about 1000 Å. The temperature of the tip of the upper opening of the evaporation source heat shield was measured using an R thermocouple and found to be 1280 ° C. However, evaporant was adhered to the upper opening of the evaporation source heat shielding structure as shown in FIG.

Comparative Example 3 As shown in FIG.
The procedure was the same as that of Example 1 except that the tip where the upper opening of the evaporation source heat shielding structure used in the above was in contact with the evaporation source was deleted. The calorific value of the evaporation source calculated from the total electric power supplied to the evaporation source was 150 kJ / sec. Under these conditions, the processing speed was 50 m / min, and vacuum deposition was performed for 1 hour.
When the thickness of the deposited film was measured using a quartz crystal film thickness monitor, it was about 1000 Å. When the temperature at the tip of the upper opening of the evaporation source heat shielding structure was measured using an R thermocouple, it was 480 ° C., and evaporant as shown in FIG. 6 was attached to the tip of the upper opening. Was.

Of the vapor-deposited films obtained in the examples and comparative examples, 20 in the film width direction at the last part of the vapor-deposition process.
An oxygen barrier property test was performed on the portion. In addition, the heat shield structure was disassembled, and each part was observed for damage. Table 1 shows the results.

[Table 1]

[0023]

According to the present invention, even when an evaporation source having a large heating value of 100 kJ / sec or more is used, quality such as breakage of parts around the evaporation source, generation of wrinkles in the film, reduction in barrier performance, reduction in tear strength, etc. The deposition process with high thermal efficiency and high production processing speed can be performed without any troubles such as reduction in quality and uneven quality.

[0024]

[Brief description of the drawings]

FIG. 1 is a perspective view of an evaporation source surrounded by a heat shielding structure of the present invention.

FIG. 2 is a perspective view of an evaporation source to which a heat shielding structure of the present invention is closely attached.

FIG. 3 is a cross-sectional view of an evaporation source surrounded by the heat shielding structure of the present invention.

FIG. 4 is a cross-sectional view of an evaporation source surrounded by the heat shielding structure of the present invention.

FIG. 5 is a cross-sectional view of the evaporation source surrounded by the heat shielding structure so that the opening end of the heat shielding structure does not contact the evaporation source.

FIG. 6 is a cross-sectional view of the evaporation source surrounded by the heat shielding structure so that the opening end of the heat shielding structure does not contact the evaporation source.

FIG. 7 is a cross-sectional view of an evaporation source surrounded by a heat shielding structure having an opening inclined at an angle of 30 degrees with respect to a vertical plane.

[Explanation of symbols]

1: evaporation source 2: evaporation source heat shielding structure
3: Evaporation raw material supply unit 4: Upper opening 5: Metal plate 6: Graphite fiber compression molded plate
7: Isotropic graphite plate 8: Boron nitride compact 9: Water-cooled pipe 1
0: Electrode 11: Aluminum evaporation material 12: Molten aluminum 1
3: Adhered evaporant

Claims (2)

(57) [Claims] 1. A vacuum evaporation apparatus comprising an evaporation source surrounded by a box-shaped evaporation source heat shielding structure, wherein said evaporation source heat shielding structure is cooled by a water cooling pipe from the outside toward the evaporation source. Opening and an evaporation material, which are formed in the order of a metal plate, a graphite fiber compression molded plate, a graphite plate or a boron nitride molded plate, which is inclined at an angle of 45 degrees or more with respect to a vertical plane, and in which the evaporated material evaporates. Wherein the temperature at the tip of the opening at which the evaporation material evaporates is equal to or higher than the evaporation temperature of the evaporation particles. 2. The vacuum deposition apparatus according to claim 1, wherein a boron nitride molded body is provided in close contact with the outside of the evaporation source.