DE2246983C3 - Triode arrangement for cathode sputtering of substances by means of an electrical low-voltage discharge - Google Patents

Description

, ^v ,, v '., _, ..? _ £ = _., -._. · .... .._ j "," η SL of electrically non-conductive materials (insulators ^

chamber (1) is electrically isolated, and that the device (7) is switched to a potential that is not is more positive than that of the wall of the atomization chamber (I).

2. Triode arrangement according to claim 1, characterized in that the partition (9) between the hot cathode chamber (11) and the sputtering chamber (1) at least on the Has an electrically insulating surface facing the atomization chamber (1).

3. Triode η arrangement according to claim 1 or 2, characterized in that the between the hot cathode chamber (11) and the sputtering chamber (1) arranged and opposite

of electrically non-conductive materials (insulators) the carrier for the material to be atomized to a High-frequency voltage was applied, there was a strong coupling of the high-frequency current in the ao direct current circuit of the low voltage discharge, whereby there is a risk of overloading the same was.

In known arrangements for sputtering insulators by means of a low-voltage discharge, »5 with which a high frequency is sent to the target at the same time Voltage has been applied, most of the electrodes are covered by the sputtered insulating material. For this reason, no dielectric layers could be produced by reactive sputtering "chambers' ΓίΓϊΐϊ eTektris ^ ToiiVrte 3ο. Further problems arose as a result. Partition wall (9) consists of metal. caused by high frequency voltage drop

4. Triode arrangement according to one of the claims, back-atomization of the substrates and the wall of the before 1 to 3, characterized in that the atomization chamber occurred.

For these reasons, the wall of the sputtering chamber (1) has usually been formed 35 known capacitive high-frequency discharge to generate and use the same potential as the sputtering of dielectric layers. However, has chamber. a " ^{ch has this} so-called diode RF discharge

5. Triode arrangement according to one of the claims. Even at relatively high pressures before 1 to 3, characterized in that the (p> 10 " ^: Torr) the carrier density in such an anode of the discharge as a separate electrode 40 discharge is low (10 '° -10 cm), so that high

Tensions are necessary to achieve the desired atomization rates. In addition to the associated structural problems, this increases the stress on the substrates from the bombardment of secondary electrons. In addition, the production capacity of such systems is limited, since the usable substrate area is always smaller than the target area. In contrast, the carrier density in low-voltage arcs has values of 10 ¹² to 10 ¹³ particles / cm '

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is switched to negative potential with respect to the atomization chamber (1).

The invention relates to a triode arrangement for cathode sputtering of substances by means of an electrical one Low voltage discharge between a

Anode in a sputtering chamber and one in a 50 on. This makes it possible with low Targetner separate, with the atomization chamber over voltages materials at high rates even in the

Sputter 10 "torr range. The substrate load secondary electrons can in this case largely by applying static magnetic fields be avoided.

To avoid the mentioned risk of undesired atomization of built-in parts and chamber walls to counter, it is known from the United States patent 3544445, parts to be protected in the Zer-

To set up support for a supply of the substance to be atomized 60 dusting chamber electrically insulated, so and also a holding device for those to be coated that they assume a floating potential during operation, Objects are provided. At this known or to put them to a positive voltage. To the The device is the atomizing inner wall of the atomizing chamber held by the carrier against the atomizing material surrounded by the anode, to protect the exercise, this was carried out by on Schwebepo atomization subject area within a potential 65 (i.e. to be set up in isolation) or Recess of the same lies. screens made of insulating material are covered.

Such an arrangement has the disadvantage that to the inside of the hot cathode chamber against To protect the risk of electrical through-ion impact during operation, this was also already included

■ **** n ^ * »■ ^ ■ • ■■■ ^^ llf IHK * pl ^ 1 ^M i ^ r 'tf iUUWUIIILtJniUllll 1 Vl% Bl ^ V * a hot cathode located in a common partition connected to the hot cathode chamber, whereby the substance to be atomized is arranged on the anode side in the axis of the discharge.

Such triode arrangements are already known (German Patent 1515294), with presence a magnetic field concentrating the discharge in the evacuable atomization chamber

provided with an insulating ceramic coating or became the hot cathode in an insulating ceramic tube located inside the hot cathode chamber housed, which could protrude a bit like a nozzle from the cathode chamber into the sputtering chamber, un; the exiting Better focus electron beam. Such measures to protect built-in parts and interior walls are, however, expensive, because they require an isolated list or for each part to be protected even a special screen and / or its own power source.

The invention is based on the object of a triode arrangement of the type mentioned at the beginning to protect the built-in parts and chamber walls against atomization by relatively simple measures. According to the invention, this object is achieved by that the partition opposite the hot cathode chamber and opposite the sputtering chamber is electrically isolated, and that the anode is switched to a potential which is not more positive than that of the Wall of the atomization chamber.

This advantageously eliminates the need to electrically connect the built-in parts to be protected set up in isolation or cover all parts of the wall to be protected with additional screens, and this makes it possible to achieve complete protection against atomization for the built-in parts and the wall of the to achieve both chambers, with internals and the wall of the atomization chamber at ground potential can be laid. This results in a structurally simple structure.

Probably the effect of the arrangement described is based on the fact that by the two of each other electrically isolated chambers oppose the plasma of the arc discharge to negative potential is brought to the walls of the spray chamber. The same goes for those on the same potential as them Chamber walls located built-in parts.

It is useful if the partition between the hot cathode chamber and the sputtering chamber an electrically insulating surface at least on the side facing the atomization chamber having. If the partition wall is made of metal, appropriate insulation must be used both chambers are provided.

The anode of the discharge can be formed from part of the wall of the sputtering chamber and that have the same potential as this. But it can also be designed as a separate electrode; in in this case it is expediently given a Po that is negative in relation to the atomization chamber potential.

The described arrangement can advantageously not only be used to coat objects are used, but also serve to this in a known manner an anodic. oxidation subject to a glow discharge in oxygen. For this purpose, oxygen is introduced into the system via a valve

ίο The following is an embodiment of the invention explained in more detail with reference to the drawing. The drawing shows schematically the evacuable atomization chamber 1. in which on holding devices 2 the to be coated with the atomized material

trending objects 3 are arranged. By means of an insulator 4 via the supply line 5, the required Operating voltage to the material 6 to be sputtered (target) through the base plate 7 into the over the pump nozzle 8 evacuable atomization chambers

ao mer introduced. The atomization chamber 1 stands through an opening in a common partition 9 with the hot cathode chamber II in connection. In this the cathode 13 is provided, gives way through the insulating flange plate 14

»5 power supply lines with heating current is supplied. Opposite both of the named chambers is the metallic one designed as a diaphragm Partition wall 9 electrically insulated by insulators 10. The glow cathode chamber acts as an ionization chamber for the gas to be ionized which is introduced in a metered amount via a needle valve 12.

A coil 15 surrounding the atomization chamber 1 serves to generate the discharge leading to the discharge Magnetic field. In operation, the base plate 7 is the

Sputtering chamber on earth potential, whereas the hot cathode 13 in the ionization chamber with the negative pole of a device 16 grounded on its positive side for generating high direct currents connected is.

If DC voltage atomization is desired, one supplied by the device 17 is applied to the target 6 negative direct voltage of a few K) OO volts or - if alternating voltage atomization is desired is, the alternating voltage (preferably high frequency) supplied by the device 18 is applied. the In the arrangement described, low voltage burns between the hot cathode 13 in the chamber 11 and the base plate 7 of the atomization chamber 1. The anode side is in the axis of Arc discharge arranged target atomized with high efficiency.

1 sheet of drawings

Claims (1)

Patent claims: 1. Triode arrangement for cathode sputtering of substances by means of an electrical low-voltage discharge between an anode in a sputtering chamber and a hot cathode located in a separate hot cathode chamber connected to the sputtering chamber via an opening in a common partition, the substance to be atomized being arranged on the anode side in the axis of the discharge is, characterized in that the partition (9) is opposite the hot cathode strikes between the anode and the walls of the sputtering chamber and the built-in components (/ .. B. holding devices) arranged in the sputtering chamber. Also άψη, if there is /.u no If any breakdowns occur, these are the inner walls of the atomization chamber and the surfaces of the built-in parts because of the potential difference between plasma and wall to some degree of atomization by impinging ions from the discharge ίο subject. This not only brings damage and an undesirable wear and tear of the surfaces mentioned with it, but leads above all to one Contamination of the layers produced in such a system. In an operating mode of the