JPH09165674A - Vacuum coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To coat a sheet with metallic oxide or a mixture of metallic oxide and metal of high quality at a high speed without generating sputtered grains by forming a crucible for holding the material to be evaporated of high m.p. metal, graphite or the like.

SOLUTION: A crucible 2 is disposed in a cylindrical acceptor 1, the upper direction thereof is provided with a coating roller 3, and the coating chamber 4 is partitioned thereby to the upper direction. A sheet 5 to be coated is continuously allowed to run via the coating roller 3. An electron beam 9 from an electron gun 8 is deflected toward the crucible 2 holding the material to be evaporated (metallic oxide such as SiO_x, metal or metallic compounds) by a magnetic coil 10. Microwave energy is brought into the coating chamber 4 by a horn antenna 11, and plasma is generated on the generated vapor lumps. In this device, the crucible 2 is formed, e.g. of high m.p. metal such as Mo, Ta and W, graphite, a graphite composite body or a ceramic material.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum coating apparatus, in which a crucible for containing a material to be vaporized is arranged in a vacuum chamber, a metal existing in the crucible,
An electron beam source for vaporizing a material such as a metal oxide such as SiO, MgO, Al ₂ O ₃ or SiO ₂ or a mixture of metal and metal oxide is directed at the crucible, The present invention relates to a type in which a base body, for example, a sheet guided through rollers is held at a predetermined distance from the material to be made to be made.

[0002]

PRIOR ART German Federal Patent No. 2628765
On the basis of U.S. Pat. No. 4,962,819, a device for depositing in particular a sublimable material in a vacuum is known. This known device consists of a container with an opening for the material to be evaporated and an electron beam source with an accelerating anode for producing an accelerated and focused electron beam. The electron beam source is aimed at the container. A horizontal bounce plate for the electron beam is arranged in the beam path between the electron beam source and the container. The lower surface of the bounce plate, which is separated from the bounce surface, faces the hollow chamber of the container, and the bounce plate leaves the outlet for the steam jet, which is provided outside the collision point for the electron beam. Covers.

[0003] Such a known device compares a generally usable electron beam evaporator with powdered material from the beginning continuously and without producing sprit particles and dust. Solve the problem of evaporating for a very long time.

Furthermore, a vacuum coating device known from DE-A-4203632 discloses a container in which the material to be evaporated is located and an evaporation for evaporating the material located in this container. And a device. The material to be coated is spaced a predetermined distance from the material to be vaporized. Furthermore, this known vacuum coating apparatus is provided with a microwave oscillator that oscillates microwaves in the space between the material to be vaporized and the material to be coated.

With such a known device, the properties of the metal oxide coating on the plastic sheet can be improved.

Transparent plastic sheets have been reinforced and used for packaging food products. In this case, firstly a sheet of polymeric plastic is conceivable. Although such a sheet is flexible, it has the drawback of allowing perfume, water or oxygen to pass through. If it is desired to avoid such material diffusion, aluminum foil or aluminum vapor deposited plastic sheets are typically used. However, such foils and sheets have the drawback of being relatively difficult to dispose of and impermeable to microwaves and light. Due to the widespread use of microwave ovens in almost every household in industrialized countries, microwave transparency of packaging materials is often crucial.

It is already known to coat polymer sheets with metal oxides in order to combine the advantages of a plastic sheet that is transparent to microwaves with the advantage of an aluminum foil that completely blocks perfume, water and oxygen. Is. In this case, silicon oxide plays a particularly important role as a coating material. Silicon oxide coated plastic sheets have properties similar to aluminum foil or aluminum coated plastic sheets in terms of their laminated structure and barrier properties to oxygen, water vapor and perfume. . However, coating a plastic sheet with a metal oxide such as SiO _x requires a process technique that is significantly different from general coating techniques. Because metal oxides are different from metals,
Because it must be evaporated from the solid phase.

The SiO _x layer is produced by evaporating SiO using an evaporation furnace or an electron beam evaporator (T. Krug, K. Ruebsam: Die neue “glaeserne Lebens.
mittelverpackung ”in“ neue Verpackung ”, Huethig
-See Verlag, 1991). Since SiO sublimes, that is, evaporates directly from the solid state without passing through the liquid phase, a special crucible is required. In order to achieve a strip sheet speed of several m / s, which is a prerequisite for economical production at an acceptable cost, a crucible adapted to the evaporation temperature of about 1350 ° C. is required. The SiO _{x -1} vapor oxidizes in a controlled, reactive atmosphere, whereby a degree of oxidation of x = 1.5-1.8 is achieved in the sheet to be coated. 2
SiO _x layers thinner than 000Å have the advantage of being easily bendable. Furthermore, SiO _x is chemically inert and has corrosion resistance to water. S
iO can be evaporated by an electron beam. This is because this SiO has a relatively high vapor pressure. However, other metal oxides such as M
Even in the case of gO + SiO ₂ , a temperature of 1800 ° C. or higher is necessary to achieve the required high vapor deposition rate.

When the metal oxide (eg, SiO _x ) is directly vaporized by the electron beam, sputtered particles are generated due to the high temperature of the oxide surface at the collision point of the electron beam. Such material particles impact the sheet and either remain attached there or even penetrate the sheet. As a result, holes are formed in the sheet that deteriorate the barrier properties. The particles adhering to the sheet cause inconvenience during later printing.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to improve the vacuum coating equipment of the type mentioned at the outset to provide metal oxides,
Or to allow the mixture of metal oxides and metals to be applied to the sheet at high speed and quality without producing sputtered particles. It is desirable for such a device to have a long service life and allow for high process stability. Furthermore, it is desirable to be able to have a particularly good lateral adjustment as compared to conventional evaporation furnaces.

[0011]

In order to solve this problem, in the constitution of the present invention, the crucible is formed of a refractory metal such as molybdenum, tantalum or tungsten, graphite, a graphite composite or a ceramic material. I was supposed to.

[0012]

According to the present invention, the sheet can be coated with the metal oxide or the mixture of the metal oxide and the metal at high speed and with high quality.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described.

A cylindrical receiver 1 is shown in the drawing. An elongated crucible 2 with an opening is arranged in this receiver. A covering roller 3 is provided above the crucible 2. The coating roller partitions the coating chamber 4 upward. The sheet 5 to be coated runs continuously through the coating roller 3. This sheet is unrolled from the supply-side roll 6 and wound on the winding-side roll 7.

An electron gun 8 serves to heat the crucible 2. The electron beam 9 of the electron gun is deflected by the magnetic coil 10 toward the crucible 10. The material to be evaporated (metal oxide such as SiO _x , metal or metal compound) is located in the crucible 2. This crucible is provided with openings, gaps or slits 15 towards the coating roller 3.

Microwave energy is introduced into the coating chamber 4 by the horn antenna 11 in order to generate a plasma in the vapor mass that is generated.

In the apparatus as described above, the cylindrical or tubular crucible 2 is uniformly heated by the electron beam 9 over the entire coating width. A slit 15 is provided on the upper surface of the crucible 2.
Is located. Through these slits, vaporous metal oxides flow out and condense on the sheet. Sputtered particle generation is prevented even at very high coating rates because the entire material is uniformly heated and vapor can only escape through the relatively small pores.

The crucible is made of a material having an extremely high melting point, such as molybdenum, tungsten, graphite, a graphite fiber composite material or a ceramic material.

In the device shown, it is also possible to ignite a plasma between the evaporator and the sheet, for example by microwave excitation. This causes the sheet to be discharged by the scattered electrons of the electron beam, which in some cases collide.

The oxygen source 12 can supply oxygen if required via a conduit 13 connected to the coating chamber 4, so that, for example, SiO evaporates and is deposited on the sheet as SiO _x .

[Brief description of the drawings]

FIG. 1 is a partial schematic view showing an embodiment of a vacuum coating apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 receptor, 2 crucible, 3 coating roller, 4 coating chamber, 5 sheet, 6 supply side roll, 7 winding side roll, 8 electron gun, 9 electron beam, 10
Magnetic coil, 11 horn antenna, 12 oxygen source, 13 conduit, 15 through hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Gerd Hofmann, Federal Republic of Germany Bruch Kabel Langstrasse 13 (72) Inventor, Reiner Ludwig, Germany Heesbach Gruntal 15 (72) Inventor Norbert Ross, Mainland, Germany Strasse 1 (72) Inventor Gerhard Steinieger Germany Roneburg Feldstraße 8

Claims (2)

[Claims] 1. A vacuum coating apparatus, wherein a crucible (2) for containing a material to be vaporized is arranged in a vacuum chamber, and a metal or a metal oxide existing in the crucible (2). Alternatively, an electron beam source (8) for vaporizing a material such as a mixture of a metal and a metal oxide is directed to the crucible (2), and the substrate is placed at a predetermined distance from the material to be vaporized. In the retained type, the crucible (2) is characterized by being formed of a refractory metal, graphite, a graphite composite or a ceramic material,
Vacuum coating equipment. 2. A vacuum coating apparatus, wherein a crucible (2) for containing a material to be vaporized is arranged in a coating chamber (4) and is present in the crucible (2). metal,
An electron beam source (8) for vaporizing a material such as a metal oxide or a mixture of metal and metal oxide is directed at the crucible (2) and at a predetermined distance from the material to be vaporized. A horn antenna for supplying microwave energy for generating a plasma in the vapor mass generated between the substrate (5) and the material to be vaporized. In the type provided with (11), the crucible (2) is formed in the form of a substantially closed container and has a number of openings, slits or through holes on the side facing the base body (5). (15) through which the evaporated material passes through the opening, slit or through hole (15),
A vacuum coating device, which is capable of flowing toward a substrate (5) and characterized in that the crucible (2) is formed of a refractory metal, graphite, a graphite composite or a ceramic material.