DE6606618U - EVAPORATION SOURCE FOR THE PRECIPITATION OF METALS FROM THE VACUUM - Google Patents

Description

* -8.8.68

PATENT LAWYERS DR. CLAUS REINLÄNDER DIPL-ING. KLAUS BERNHARDT

D-8 MONKS 60

BÄCKERSTRASSES _s6 p _40D

SYLVAN] [A BtECTRIC PRODUCTS IHC. Wilmington * Delaware V «St * v * America

Evaporation source for the precipitation Yüä Ketäiiön from the Väkuurä

Priorities «August 10, 1967 United States of America US Serial Numbexe 659 777 and 659 747

Summary"

Ea is turned over to a source of evaporation for precipitation Toa Metallen * ue d «m vacuum described, the« in resistance heating element from interleaved coils from hooh = having melting metal wire. An elongated, heat-resistant (refäas with a cavity to accommodate the to evaporate = the metal is carried and heated by the heating element there is a barrier between the cavity and the heater, to prevent overflowing liquid metal from getting with the To come into contact with the heater "

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State of the art:

The invention relates to evaporation vessels for use When coating objects with metals, the metal is reduced to its evaporation temperature under vacuum uiad dan'ci is heated on the object to be coated is precipitated, and in particular such an evaporation vessel, which entails the steaming rietail charge below. holds, but the heating element did not form itself

Electrically conductive, heat-related heating elements have already been used to heat metals such as aluminum, silver, Cadmium and the like evaporate, but they suffered • really strong? Corrosion from the liquid, evaporating Metals, or under thermal cracks due to the high operating temperatures. In addition, the Heiaäement in

Breaking operation due to normal thermal expansion, or because

Tensions on the solid element came when the ends were clamped tightly and nods in completely flexible attachment « Posts were jammed · Elements of this type have been made from graphite, titanium boride, titanium carbide, and the like

£ β are also evaporative heaters made of high-melting wire alone manufactured, for example tungsten, HolyMän and tantalum,

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■ however, they generally had a short lifespan Corrosion of liquid metal, such as aluminum, that evaporates

5 was o

Summary of the Invention t.

f | According to the invention, a regular evaporation source is used

I made joinable that were essentially resistant to corrosion

I am through the au liquid metal evaporating and not cracking

I shall be subjected to that exerted on the item if its

I ends in the fastening to establish the electrical connection

I post jammed. It becomes an elongated evaporation =

I used a vessel that has a cavity that can be used

I contains steaming metal, and liesee is made from a vessel

p made of heat-resistant material that against the netall

I whose evaporation temperaturea is corrosion-resistant »Das Sefäss

I is carried and heated with a new type of resistance heater,

I from a rush of nested coils

p is made of refractory metal? You stick out ends of the heater

I over the ends of the vessel and are with the retaining posts

■ connected to a yakuun precipitation plan and from

this is borne, and the stoker is flowing through it electric current heated "

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The flexibility of the HetRkon; rukt, ion allows the heater to absorb stresses that result from the thermal expansion or from small misalignments of the support posts the ends are clamped without damaging the heater. In addition, these tensions are not transferred to the evaporation vessel because there is no strong connection between the vessel and the heater. You life Yerdampfungsquell · is thus extended by the fact that the source of error, such as metal corrosion d "is Gefäsaeo or terminal voltages are reduced _o

Another part of the gate of the evaporation source according to the invention is the uniformity of the electrical resistance, which mainly depends on the structure of the heating network. This can be important in semi-automatically controlled mass production facilities,

! where desired, substantially constant Hoizer currents and

Maintain precipitation rates even when the evaporation sources

be exchanged »That is not possible with the alektrlooh conductive, heat-resistant elements that were previously used, because their resistance differs considerably from element to element.

Also, the heater itself is exposed to corrosion through the metal, as already mentioned, and around its contact with the heater

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to prevent overflowing liquid metal A lock is arranged between the cavity and the heater. This lock can be a protective sleeve around the heaser, or a channel or the like in the surface of the vessel, with the overflowing metal from the exposed ends of the heater »egleitung virdo Through such a lock the corrosion of the heater is also prevented by the metal overfing it, so that the service life of the inventive • The evaporation source is increased even further.

The invention is to be explained in more detail with reference to the drawing will; show it:

Fig. 1 is a perspective view of a ketallic evaporation source according to the invention;

Fig. 2 shows the heating element “only its central part is indicated schematically;

Figo 5 shows the Netsikonstruktion dos heating element;

4 shows a perspective view of a second embodiment. an inventive evaporation source;

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Pig. 5 shows a further embodiment of the invention; and

Pig. 6 the individual components of the embodiment according to FIG. 5.

A heat-resistant vessel 1 according to the invention consists of a heat-resistant material which is essentially resistant to corrosion by the liquid metal to be evaporated and which is practically inert to operational conditions. A cavity 2 is arranged on the top 6 of the vessel and serves as a container for the metal to be evaporated. It is desirable to limit the metal charge in the cavity 2 to an amount that is suitable for semi-continuous operation without the need for too high a heater temperature, the depth of the cavity 2 is therefore preferably less than 1/3 of the depth of the vessel 1- In the ideal case, the cavity 2 is arranged in a neat manner on the surface 6 in order to protect the thermal tension Reduce minimum that can result from an unequal wall thickness around the cavity 2. A heater compartment 3 is in the lower part. of the vessel 1 arranged in the longitudinal direction and has suitable dimensions so that a mains heater 4 can be used in this. For optimal heat transfer from the heater 4 to the Gofäss 1, the cross-sectional area of the compartment 5 should be as small as possible, taking into account that the

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Heater 4 can be used easily. Preferably, as £ compartment 5 is in Gefäse 1 arranged in such a position eiuer _s that the thickness of the side walls is substantially equal to thermal stresses xu Decrease, the starch out of unequal wall in Gefäse = 1 may develop.

L ^ s? ^ 'hag'fcch'fc gng individual interleaved coils »First, straight pieces of high-melting wire are individually wound around an egg, with each turn being separated from adjacent turns so that individual coils are formed. After removing the kernel, two coils are threaded into each other, a third is threaded into the second, a fourth is threaded into the third and this continues until a mat of interlaced or nested spirals is obtained. The material is then arranged longitudinally around an elongated peg so that the first and. the ietste Wendel liegei together. and it vill another spiral by the first and last Wencel threaded to die3e au unite ^ Bach earth removal from the pin "the ^ ends vezschveisstj, van

the helical ends to be fixed securely and an integral, flexible one Form heating element in which lie individual bobbins freely be able to stretch and pull together. In a goal wizd a staff made of the same metal inserted into the endea of the heater and

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there voroohweisot to keep the temperature of the sanitary towels below the deB Body of the heater in operation.

The heater 4 is then bo in the compartment 3 of the vessel 1 a » Assume "that essentially equal amounts of the heater 4 protrude from the ends of the Gofaeees 1" The heater 4 does not fit just in the compartment 5 "it", however, there is sufficient surface contact, so that the GoffisE 1 can be attached to it with force prevent yourself because of its own weight against the Heater 4 to move alone *

In operation, the ends of the pickle 4 with the vessel 1 carried by it are clamped to holding posts or other holding devices in order to supply electrical power to the heater 4 in general to a vacuum chamber. In the chamber, provision is made to ensure that the object to be coated is brought into line of sight with the cavity 2 so that the metal vapor rising therefrom condenses and precipitates on the object 2 a = brought and the pressure in the "'' akuumkamiaer is then reduced to less than 0.001 Torr. Dome heater 4 is supplied with sufficient electrical power. in order to heat the ketallcharge at the chamber =

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precipitates inside the chamber »In a semi-continuous coating process, for example if a continuous Roll made of plastic film is to be covered with aluminum, provision is made in the vacuum chamber to ensure that the film can be continuously unwound from a roll, via the Passed cavity 2 and the foil on a spool is wound while the aluminum is continuously evaporated. The jellyfish for Alioninius for hemstitch 2 is a coil of aluminum wire in the chamber, with the free end of the wire going into the cavity The speed is unreeled from the spool so that a substantially constant charge of molten aluminum is in the The cavity remains, i.e. about the same rate of evaporation of the aluminum o The heater 4 is supplied with sufficient electricity fed to get the desired Vurdai vaccination rate »

In a special embodiment: an evaporation source according to the invention for the semi-continuous evaporation of aluminum was milled into a vessel 1 from a solid block of boron nitride, since 3 at the temperatures that occur, it is essentially resistant to tungsten and molten aluminum ο the vessel 3 ha- ote a length of 41 mm (1 5/8 inch) a width of H mm (9/6 inch) vni. a depth of 17.5 mn- 1/16 inch) ₀ The cavity 2 was sleek in the

= 10 =>

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Top 6 long and was about 35 mn (1 5/8 in) long, I.

11 mm (7 / ί6 JSoIl) wide and 3 mm (1/8 in.) Deep. The compartment

5 was formed in that a hole drilled along wtsä.e of 11 now (7/16 inch) diameter! Through the vessel in the lower part ₉ "obei the wall thickness s' f dsr underside of 1.6 mm Gefässeu Ci / l6 inch ) was "Di" underside of the vessel was rounded down so that the wall thickness around the entire lower half of the compartment was about 1.6 stm (1/16 inch) throughout.

The heater 4 consisted of 18 interleaved tungsten filaments made by placing a 1 mm (0.040 inch) diameter tungsten wire on a 1.5 mm (0.060 inch) diameter core with a pitch of about 2 1/2 turns each 6 1/2 turns per inch. "Kaoh removing the core, each coil was trimmed to a length of 100 mm (4 inches). 17 coils were then interleaved with one another to balden a Had the-cylindrical then to sinen zyliii "pin of 5 _f 2 mm (i / iJ inch) diameter brought vnard ^ _f and the eighteenth Vfeadel was by the first and sieczehn '' Wendel threaded so that a cylindrical network of 100 µm (4 inches) in length with an outside diameter of about 10 mm (! 5/32 Z> 11) was created. β in) diameter and 25 mm (1 in) length in

= 11 =

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each end of the hoarse 4 inserted and the ends of the hoarse » 4 Heliare were forgotten, over the rods and coils sit « connect each other su. On WoIframetab 5, TJm = would be aaoh. to be sieved "

H ^ t Ssissr 4 V £ r £ s ^ g * ??? used as in the compartment 5 de ^H Q «£ fiseea 1" that etva 30 mm (1 3/16 inches) on each end of the vascular & sses 1 produced stan dent. Itaa evaporation element was then mounted in a vacuum depressurization chamber and approximately 25 mm (1 inch) of each end of the hoarse 4 was clamped with water-sealed, copper, half-battery support pads. Inside the TakuumkaBunor was a device by which the aluminum wire was continuously fed into the cavity "The pressure in the chamber was" reduced "to less than 0.001 Torr and AC voltage was applied to the support posts

about 500 amps flowed through it. The temperature of the I βίο It was about 150 ° C, the temperature of the vessel about

1400 C, and the aluminum was at a rate of 4 g pxo

Hinute Terdsmpfto

During the start-up, at dom the delivery rate of the aluminum is adapted to the evaporation rate, the cavity 2

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if a lot of old age has been delivered

Having seen that, overflowing setall can flow to the heater in the Koaaen touch and corrode it.

In the embodiment according to FIG. 4, therefore, bind between the

arranged, di · generally across the longitudinal dimension of the ge » Barrel 1 is enough, but a distance between the grate and cavity 2 End of the vessel 1 · The channels 6 extend at least over the entire surface 6, however, the sides of the vessel can also be rearranged. To. The width and depth of the channels 8 are usually small compared to the size of vessel 1 and theirs Task "is to get liquid feces that over the cavity flows away from the heater 4 »Die Quersohnittsfläohe der Kält »8 must not be too small, however, so that the surface tension of the liquid metal prevents it from flowing under the influence of gravity in the channels 8 from the heater 4 veg» When the liquid metal floods the cavity 2, the conduct Channels 8 it out & lb near down to the bottom of Gefäoaee 1, where it drains harmlessly, generally on a brain on Bodon the Niedörsohlsgekanimer.

In the embodiment according to FIG. 4, the structure of the gleloho is like in connection with? ig. 1 explains, in a special car

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however, other funds were used. The vessel was 54 mm (2 1/8 ") long, 14 m (9/16") wide, and 27 mm (1 1/16 ") deep. The cavity 2 is arranged with var tig izi the upper side 6 and about 35 mm (1 ^5/8 inches) long, 11 am (7/16 inch) dreit xa> i 5 ₈ 2 mm (i / 8 inches) deep. Sas compartment 3 also constructed var vie the NaOH in the Ausfühxungaform Fig. 8 to the channels were milled 3 _S 2 mm (1/8 inch) from each end of the vessel 1 around and have a depth and width of 3.2 mm (i / S ZoIl) ₀ They formed an effective barrier between cavity 2 and heater 4 - In consideration of the greater length, the length of the heater and the individual heating coils were 115 mm (4 1/2 inches) each. «-

In another embodiment of the invention see Figo 5 and 6, the barrier between the cavity 2 and the heater 4 is an elongated heat-resistant sleeve 9. The sleeve 9 is around the Heater 4 arranged around and prevents direct contact between the heater 4 and the vessel 1 »This sleeve 9 existed in the illustrated embodiment made of boron nitride and had an inside diameter of 11 minutes (7/16 inch) and a wall thickness 0.8 mm (i / 32 inches). The compartment 3 then has a diameter just over 13 mm (1 / ½ inch) and the diameter of the heater was slightly under "! 1 mm (7/16 in.). When the heater 4 is in the sleeve 9 was inserted, and both were inserted in compartment 3,

= »Τι 4 = *

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each about 13 mm (1/2 inch) of the sleeve 9 protruded from the ends of the vessel 1, and 25 mm (1 inch) of heater 4 protruded from the ends of the sleeve 9. Hit these protruding ends, the heater 4 can be clamped to the support post again. When liquid metal flows over the cavity 2 and the top 6, it can flow onto the protruding parts of the sleeve 9 at the ends of the vessel 1. In order to prevent a build-up of liquid metal on the sleeve 9, which could then flow over the ends onto the exposed ends of the heater 4, the upper sides of the sleeve 9 are beveled or curved, preferably convex. The tietall then flows down and from the

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Sleeve 9 off, but not out at the ends «

In operation, the sleeve 9 is generally at a higher temperature = door as the vessel 1, because it is closer to the Heiser 4 is uad not directly cooled by the evaporating metal "The sleeve t 9 feat iT i be gencg therefore sometimes hot to iiberfliessendes to evaporate liquid metal, even if the vessel 1 is not hot enough to prevent flooding *

Another possible cause for having liquid 3 fete] 1 with The fact that heater 4 comes into contact is due to the surface tension « Weoa dae Gef & oo 1 is slightly wetted by liquid metal, k ^ m see the metal spread out and on the surface of the vessel 1

- 15 ~

crawl »When for example d & s vessel 1 made of graphite or

Boron nitride and the liquid ketall aluminum with a If the temperature is above about 14ΟΟ C, the liquid aluminum wets

the surface of the vessel 1 and gradually spreads from the

Block the flow of the molten metals from the exposed ones Hoarse by looking the length of the way over the heater ends and the cavity 2 is significantly increased

Instead of bucket continuous sleeve 9, two shorter ones can also be used Sleeves made of boron nitride are used, dl «about ta» the same Amount protruding from the vessels 1 like the continuous HO. as, but not completely through the compartment 5 o

The vessels and sleeves described were made of boron nitride, however, other materials can also be used

resistant to aluminum and tungsten _s are for example Aluminiemnitrid "^ itankarbid, zirconium diboride and ^ itanborid or any combination or fälsohung vea this, w © nn Alttminiam oa e the \ Steam should be suppressed, since all these substances are made of »

] are sufficiently resistant to corrosion for the Zveoke according to the invention «

\ The deal and pods can be made auoh dadureh,

that the heat-resistant powder rose into a graphite structure

\ - 16 -

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is pressed, which is shaped to relax. Or they can duroh cold pressing dos with heat-resistant powder or by pouring a slurry of this powder into a suitable shape This is followed by a high-temperature sintering process in order to maintain the required stability and strength In addition, the basic idea of the invention can be applied to vacuum deposition other metals such as gold, silver, chromium, nickel and the like can be used if the heat-resistant one is to be used The correct material is selected with reference to the resistance to corrosion of the heating element and the metal to be evaporated willo The compounds mentioned are for example also suitable for vaporizing gold, silver and copper »

A cylindrical net heater has also been described, other shapes such as polygonal shape, elliptical or semi-flat cross-sections can also be used. These shapes are made by applying the mat made of woven coils to an appropriately shaped pattern and attaching it, and welding the ends of the heating elements to the desired shape; , tantalum Odei .zelement from other Widerstanda ^ rt you came wires are made from hochschmelzendon metals having a melting point of more than 2000 ⁰ C, for example, molybdenum, niobium ,, ^1: ,, are in the scope of the invention also lies in that the Netzhe

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Claims (1)

RA. 4 6 19% IHL 8th week 36 P40 D - Bnebrueh 1 · Evaporation source for the deposition of metals in a vacuum, consisting of a heater and a heat?) "" Permanent vessel with a cavity on the top, characterized in that the heater is a Widexstands heating element ₉ made up of interleaved coils of biahtans hoohschmelsendeB Heiail "ordered, whereby the turns of the coils are held to the turns of adjacent coils, so that the individual turns can freely expand and contract, and the hit-resistant Gerfass is elongated, is supported by the heating element and ▼ on that can absorb heat « 2. Evaporation source according to claim 1, characterized in that that the wire made of high-resistance metal is made of tungsten " 3 · Evaporation source © according to claim 1 ocier 2 ₉ dacurcsh gekeniise: .oh = net that the depth of the cavities is less than 1/5 of the Ti.äfe:. «Ε vessel lake. 4 · Evaporation source according to claim 1, 2 or 5 »dadurea j i'xenrizeichnet, that the heater is cylindrical * 660661822.10.70 A2 - 5 »Evaporation source according to one of: Claims 1 ~ 4 * i marked that the vessel has an elongated compartment, in which the heater is arranged and its father's son preferably adapted to the width of the hoist is. 6. TexdaEpfnngsqnelle according to any one of claims 1-5 * thereby ^r · 'marked that the booths of the heating «leoente8 over the Ends of the vessel henrc; stand. Fe Vefuämpfuugsquelle according to one of Claims 1-6, characterized in that the container consists of boron nitride * 8. Terdampfungsqviells according to any one of claims 1 -7 * daduroh characterized in that a device is provided with which to. evaporating metal is prevented from working with the To come into contact with the heater " 9. VerdampfungsquelIe naoh claim 8 ₄ characterized et, that the device consists of a lock between the cavity and the element, 660661822.10.70 10, evaporation source? according to claim 9 »characterized in that that the lock from e: aie: r recess in the vessel between the ends of the cavity and the ends of the vessel a which extends at least over the top of the vessel and is arranged at a distance from the cabbage room " 11. Evaporative source according to claim 9 or 1O _9, characterized in that the barrier "consists of ice & in elongated heat-resistant element, which is arranged between the heater and the vessel, wherein iie ends of the element are arranged between the ends of the vessel lake and the heating element"