DE1276977B - Method and device for vapor deposition of thin, even layers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN fflTWGS » PATENTAMT Int. CL:

C23c

EDITORIAL

German class: 48 b -13/00

Number: 1276 977

File number: P 12 76 977.6-45 (N 26428)

Filing date: March 22, 1965

Open date: September 5, 1968

The invention relates to a method for vapor deposition of thin, uniform layers from a melt in a crucible, the surface of which is partially kept free of slag, as well as devices for performing this method.

If thin layers are to be vapor deposited, it is generally necessary to take care of that that the properties of the layer are deposited over the entire surface onto which the material is deposited will, are even. An example of a case where it is necessary to apply a uniform layer, is the manufacture of a memory for an electronic calculating machine, being an ordered one Amount of elements, which consist of small areas of a thin nickel-iron layer, using a mask is vapor-deposited onto a base.

The thickness, composition and physical properties of the layers depend on radial Variations in the incident bundle and from the angle at which the material touches the surface got off.

With a suitable vapor deposition device, the radial fluctuations in the vapor flow and the fluctuations in the composition will be small, while the amount of evaporated material will be large must be so that the device can be used at a greater distance from the surface, thereby minimizing fluctuations due to changes in the angle of incidence will.

In known vapor deposition devices in which the material to be vapor deposited is melted in a crucible slag forms on the surface of the molten metal; H. a foam, which consists of oxides or other compounds that cannot be melted at the temperature used, which are present in the material to be evaporated or formed during the melting process will. This slag can cause fluctuations in the surface temperature and covers the effective evaporation surface partially, causing radial changes in the steam flow will. Fluctuations in the surface temperature of the material to be vapor deposited, if It is an alloy, moreover, differences in the composition of the vaporized Material result.

Evaporation methods are also already known in which the disruptive slag or oxide layer floating on the bath surface of the molten vapor deposition material is removed (German method and device for
Vapor deposition of thin, even layers

Applicant:

N. V. Philips' Gloeilampenfabrieken, Eindhoven (Netherlands)

Representative:

Dipl.-Ing. H. Auer, patent attorney,

2000 Hamburg 1, Mönckebergstr. 7th

Named as inventor:

Ulrich Pick, Thornbon Heath, Surrey;

John Chadwick Brice, Reigate, Surrey

(Great Britain)

Claimed priority:
Great Britain from March 24, 1964,

dated December 1, 1964 (12 371)

Auslegeschrift 1043 010, German patents 812 025, 816 933, USA patent specification 3,016,873). For this purpose, however, additional measures and device parts, such as settling containers and pulling devices, necessary.

The invention is based on the object of a method on vapor and devices for performing to create this process in which the adverse effect of the during the melting process The slag formed is reduced without the need for additional containers and extractors are required, and at which an almost identical temperature over the entire evaporation surface occurs.

This object is achieved according to the invention by a method which is characterized in that the crucible is filled so high with material to be evaporated that the curvature of the surface of the melt is removed is always above a certain critical curvature during vapor deposition, so that the slag collects at the edge zone of the melt surface and free the middle zone leaves.

An apparatus for performing the method according to the invention is characterized by a crucible made of a material with good thermal conductivity, which is surrounded by a jacket, of which one

809 599/449

Claims (1)

3 4 Part protrudes beyond the rim of the crucible, and a heating rigsten part of the meniscus is drawn. Electrons off wire for heating the crucible and the jacket. the heating wire 2 bombard the jacket 3, to wel- A device for carrying out the purpose is preferably a potential difference of at most Ren the method according to the invention marked 5 kV between the heating wire 2 and the jacket 3 is characterized by being applied electrically 5 from a jacket. The focus screen 1 will open The crucible surrounded by conductive material is kept at the same potential as the heating wire 2. resistant ceramic material, a heating wire, the jacket 3 protrudes beyond the crucible 4, whereby the which can serve as an electron source, and a better shielding surface of the material to be vapor-deposited. heats up. An example of a vapor deposition device according to the io The dashed lines above the surface The invention and a method of using this of the material 6 give one possible location of the upper device According to the invention are below the surface of the material 6 before the start of the evaporation Hand of the drawing explained in more detail, the scheme at. table shows a vertical section through the device If the material 6 is a nickel-iron alloy represents. 15, care must be taken to ensure that the melt The vapor deposition device consists of a non-flowing over the edge 7 of the crucible 4, whereby shielding (focusing screen) 1, a heating element, the molten alloy with the molybdenum mandrel 2, a jacket 3, a crucible 4 and a tel 3 would come into contact , because in this electrically conductive carrier 5. The case to be vapor deposited would result in a three-component alloy, the material 6 can, for. B. a nickel-iron alloy 2 ° has a lower boiling point than the nickel and is in the crucible 4, which is made of zirconium-iron alloy. oxide or aluminum oxide. The jacket 3 was The temperature of the nickel-iron alloy was is made of molybdenum and protrudes beyond the edge 7 of which in a certain case is kept at about 2000 ° C. Crucible 4. The focusing screen 1 surrounds the It is advisable not to evaporate more than 20% of the initial ring-shaped heating wire 2, which consists of two together- «5 amount of the alloy, because otherwise twisted tungsten wires with one diameter each can change the composition considerably. It consists of 0.2 mm. The material 6 has a convex surface, which has been found to be 25 cm apart, which consists of a main area 8, between the evaporation device and the underneath the evaporation without hindrance by a layer of an alloy amount of 0 .25 g of any slag that may be present on zone 9 along the rim 30, which is 1000 Å thick, which is limited to 7, can take place. The gas flow was at most 6 · 10 ~ ⁷ g per square In a practical embodiment of the invention grad and had at a distance of 15 ° from the the following "dimensions were chosen: Axis decreased by less than 6%. The jacket 3 and the crucible 4 can be made of uniform outer dimensions of the jacket 3 .......... 15 mm ₃₅ from the same material. The height inside dimensions of the shell 3, above ..... 13mm of ^the walls of the shell 3 must be greater than the _T , ~ - ·, _ maximum height of the material 6. In this way Inner dimensions of the outer jacket 3, below 9 mm _{, is} achieved that the radiant heat of the walls Outer height of the jacket 3 11 mm of the jacket 3 the entire surface of the T "" _a ™ nxi, = A _ar , \ / r + "i" io ~~ 40 of the material6 heated. When the crucible4 Inner height of the mantle 3. 8 mm . ,,. . ,. ,,. ,, «·. , - ^. made of an electrically non-conductive material, e.g. B. Outer height of the crucible 4 4 mm aluminum oxide, can also be made on a Inner height of the crucible 4 3 mm other than by electron bombardment, e.g. Am- XT7 jj · 1 j rr, -, »- * ductive, to be heated. In this case he needs Wall thickness of the crucible 4 1 mm _{45 Carrier 5} ^^ _{loading to sekj he must however be possible} _ The diameter of the carrier 5 2 mm can be thin to reduce the heat loss of the crucible to a minimum. The material With the above dimensions, the crucible must have good thermal conductivity, and it has been found that the convex surface requires an initial amount of 2.5 g of a 50:50 nickel crucible 4 for vaporizing tin and the jacket 3 made of molybdenum-iron alloy exceeded. The surface of the can stand.
Materials 6 still retains the critical curvature claims
curvature exceeding straight if 20%> der Initial amount has evaporated. Experiments have shown that if the largest diameter of the inner layers of one side of the crucible is D cm, the evaporating melt, the surface of which remains partially free of slag if their is kept free of slag, thereby •• ß + XT-T, -κ 1 Z ^{0 '74} na \ "· ν 1 ι indicates that the crucible so tall, Greatest height greater than (- ^ - 0.6 cmj for nickel- to be vapor-deposited material that is Iron alloys is. 60 the curvature of the enamel surface during A ball made of nickel and iron with vapor deposition always above a certain predetermined volume, which is located by pressing and th critical curvature, so that Sintering is produced in a hydrogen atmosphere, the slag at the edge zone of the melt surface is placed in the crucible. The crucible is slowly collected on the surface and the central zone is left free,
heated in order to expel any trapped gas. ben. During the melting of the ball, the rens according to claim 1 is characterized by A crucible (4) made of a highly thermally conductive crucible, possibly forming on the metal surface Slag due to the surface tension to the low material, which is surrounded by a jacket (3) a part of which protrudes beyond the edge of the crucible, and a heating wire (2) for heating the crucible (4) and the jacket (3). 3. Apparatus according to claim 2, characterized by one of a jacket (3) from electrically crucible (4) made of fire-resistant ceramic material surrounded by conductive material, a heating wire (2), which can serve as an electron source, and a shield (1). Documents considered: German Patent Specifications No. 812 625, 816 933; German Auslegeschrift No. 1043 010; U.S. Patent No. 3,016,873. 1 sheet of drawings 809 599/449 8.68 © Bundesdruckerei Berlin