CN1513199A - Device for supplying power to cathode of arc evaporation device - Google Patents

Abstract

The invention relates to a device for supplying power to a target electrode (16) forming the cathode of an arc evaporation device for evaporating the target electrode by means of an arc spot generated by at least one arc current between an anode and a cathode, wherein the target electrode is electrically conductively connected at least to the periphery of a support (20). In order to ensure the desired and uniform evaporation of the target electrode material, a plurality of electrically conductive connections (38, 40) which are distributed over the peripheral region of the target electrode and are electrically conductively connected to one another from their side by electrical connections (42) are led out of the support (20) and/or the target electrode (16).

Description

Apparatus for supplying cathodes of arc evaporators

technical field

The invention relates to a device for energizing a target electrode constituting the cathode of an arc evaporation device for evaporating the target electrode by means of an arc point generated by at least one arc current between the anode and the cathode, wherein the target electrode is electrically conductive at least with the periphery of the support Connection, the support itself is connected via at least one electrically conductive connection to a power supply connection distributed outside the evaporation device.

Background technique

EP 0 306 491 B1 discloses a device of the above-mentioned type. To apply the alloy layer to the component, a target electrode is used which has at least two different metals in its different active surface segments. In an arc vaporization device according to DE 42 43 592 A1, the target electrode is supplied with power via an excitation coil in order to move the arc spot along a random trajectory.

Regardless of the type of misconnection of the magnets or the configuration of the target electrode forming the cathode, the point-by-point supply of this target electrode has the consequence of producing different impedances depending on the arc point on the target electrode to the current interruption position. This change in impedance leads to increased branching of the arc and consequently increased droplet emission from the surface of the target electrode. Such drops cause the surface of the part to be coated to be rough and thus lead to an undesired impairment of the quality of the coating. A change in impedance, ie a change in the arc voltage at a predetermined arc current, is even more dangerous because the control system/control electronics do not recognize this change, so that the operator of the plant cannot be sure of the repeatability and quality.

Contents of the invention

The present invention is based on this problem by improving a device of the above-mentioned type in such a way that the desired uniform evaporation of the target electrode material is carried out independently of the position of the arc point, so that the substrate arranged in the arc evaporation device or its vacuum chamber is uniformly coated. layer.

According to the invention, this problem is basically solved by leading from the support and/or the target electrode a plurality of electrically conductive connections distributed in the peripheral region of the target electrode, which are themselves electrically conductively connected to each other by wires. In this respect, in particular point connections, which can be formed by pins, screws, rivets, bolts or the like, are electrically conductively connected to one another via rings, in particular closed rings. The arrangement of the conductive connection involving the target electrode is achieved in such a way that the same or substantially the same impedance is formed on the target electrode independently of the position of the arc point, it goes without saying that during processes such as pressure, bias, etc. with the same parameters.

Furthermore, a foil with good electrical conductivity, in particular copper foil, is arranged between the target electrode and the support.

The wiring itself, which runs outside the arc evaporation device and forms the electrically conductive connection to the target electrode, is preferably a ring wire made of copper, while the electrically conductive connection to the target electrode or its support itself can consist of brass. Any material with a very high electrical conductivity can be used as target electrode material.

Independently of this, in order to obtain a uniform impedance, the electrically conductive connection develops an envelope, the coaxial periphery surrounding the effective free surface of the target electrode. In particular, a quadrilateral geometry is formed, wherein the same or substantially the same distance between the electrically conductive connections is maintained along each side of the quadrilateral. The connections leading from the parallel or substantially parallel running sides of the envelope likewise have the same distance.

According to the present invention, power is always supplied directly to the position where the arc point is generated on the target electrode, and the same impedance is always generated on the basis that it does not depend on the position of the arc point.

This results in a minimal disturbance of the magnetic field acting on the arc point, resulting in a uniform galvanic erosion or evaporation of the target electrode within the desired range, without the risk of drops being generated from the target electrode, entering the vacuum chamber, This results in an uneven or rough surface of the substrate to be coated. In other words, there is an optimal support - or guiding effect - of the magnets acting on the arc point.

The composition of the connections is simple in design. The target electrode and the support can be machined flat, wherein in the usual manner there is a gap between the support and the target electrode to which cooling water can be supplied.

Description of drawings

Further details, advantages and features of the invention result not only from the claims cited with reference to them - on their own and/or in combination - but also from the following description of preferred exemplary embodiments with reference to the drawings. in:

Fig. 1 shows the schematic diagram of target electrode device;

Figure 2 shows a schematic diagram of a target electrode with an arc spot.

Detailed ways

In FIG. 1 , an arc evaporation device is shown in a purely principled manner with a vacuum chamber 12 surrounded by a housing 10 in order to process, for example coat, a substrate 14 inside the vacuum chamber 12 . Here, in the examples, a hard material coating device was used.

In order to coat the substrate 14 which can be arranged on the turntable, the material present in the target electrode 16 in the vacuum chamber 12, such as a titanium target electrode or other suitable target electrodes, is evaporated, these materials are mixed with e.g. _N2 or _{C2H 2} The reactive gas reacts and deposits on the substrate 14 in the desired range. For this, a voltage is connected via a power source 18 between the target electrode 16 and the housing 10 , the housing 10 being the anode and the target electrode 16 being the cathode. In this regard, however, the applied voltages involved are, for example, of the order of 20 V and the currents of the order of 100 A, referring to the perfectly known art. Depending on the application, the pressure value in the vacuum chamber 12 can be, for example, in the range of 0.0001-0.1 bar.

Target electrode 16 emerges from carrier 20 , which is electrically insulated from its side by an insulator 22 , for example, from a flange plate 24 made of aluminum, which is connected from its side to housing 10 . Between the target electrode 16 and the carrier 20 there is an interspace 26 , in order to cool the target electrode 16 in the desired range, a cooling fluid such as a liquid is applied. The target electrode 16 has an annular collar 28 at the bottom end, so that it is positioned between the carrier 20 and the fastening plate 30 . The fixing plate 30 itself is covered with an insulator 32 made of, for example, BN, and is connected to the bottom plate 24 via insulators 34 and 36 .

The carrier 20, the fixing plate 30 and the target electrode 16 are electrically conductively connected via bolts or screws 38, 40 or equivalently acting elements to a wire 42 as a ring wire, that is to say, the screws or bolts 38, 40 are connected to each other and to the power supply 18 superior. The other pole of the power supply 18 leads to the housing.

The housing 10 forms the anode, the carrier 20, the cover plate 30 and the target electrode 16 form the cathode, wherein only the target electrode 16 is exposed with its surface 42 in the vacuum chamber 12, so that the anode, that is, the housing 10 or its wall and the target electrode 16 An arc and thus an arc spot 44 can be formed in between, the movement of which along the surface 42 is determined by the magnet 46 (MAC=magnet arc limitation), ie its magnetic field, present below the target electrode 16 and outside the vacuum chamber 12 .

According to the invention, a plurality of electrically conductive connections 38 , 40 interrupted in the peripheral region of the target electrode 16 run through to the support 20 and thus to the insulator 22 of the target electrode 16 , which are connected to the power supply 18 via ring lines 42 . In this case, the electrically conductive connections 38 , 40 have the same distance from one another, at least in the sides of the target electrodes 16 running parallel to one another.

If the target electrode 16 in top view has a rectangular geometry, the contacts 38 , 40 likewise develop a rectangular geometry, ie form a corresponding envelope. Thus, regardless of the position of the arc spot on the surface 42, essentially the same impedance results, with the result that the target electrode 16 evaporates uniformly, whereby the substrate 14 to be treated or coated obtains the desired surface quality.

FIG. 2 shows a purely schematic view from the bottom of the target electrode 16 with the ring wire 42 and the base plate 24 shown in principle. In addition, the electrically conductive connections 38 , 40 , in particular formed as screws, leading out of the ring wire 42 are shown in principle, by means of which it is shown that they are distributed at the same distance from one another along the longitudinal sides of the target electrode 16 , wherein the screws 38 , 40 are arranged along the The parallel sides are at equal distances (cf. equal distances b or d within the range of the respective parallel running edges).

It has already been mentioned that the ring conductor 42 preferably consists of copper, whereas the screws or equivalently serving contacts 38 , 40 may consist of brass.

In addition, in order to obtain desired uniform power supply, a foil with good conductivity such as copper foil is provided between the target electrode and the carrier 20 and, if necessary, the fixing plate 30 .

Claims (8)

1. be used for device to target electrode (16) power supply of the negative electrode of arcing vaporising device, the electric arc point that is used for producing by means of at least one arc current between anode and the negative electrode evaporates the target electrode, wherein, the target electrode is connected with the peripheral conduction of support (20) at least, this support itself connects (38 by at least one conduction, 40) be connected in the power supply wiring (42) that distributes in the vaporising device outside, it is characterized in that, draw a plurality of conductions connections (38 that in the outer peripheral areas of target electrode, distribute from supporting (20) and/or target electrode (16), 40), they are own by wiring (42) connection each other in an electrically conductive.

2. by the described device of claim 1, it is characterized in that the conduction of leading to negative electrode (16,20,32) connects (38,40), and conduction connects by the wiring (42) that constitutes as ring, particularly closed-loop.

3. by claim 1 or 2 described devices, it is characterized in that conduction connects (38,40) and is arranged on like this on the target electrode (16), makes the position of not depending on each electric arc point (44) form identical or essentially identical impedance.

4. by aforementioned claim described device one of at least, it is characterized in that, at target electrode (16) with support the paper tinsel, particularly Copper Foil that setting is made by the good material of conductivity between (20).

5. by aforementioned claim described device one of at least, it is characterized in that preferably the wiring (42) that constitutes as toroidal conductor is made of particularly copper or aluminium or the material that contains them.

6. by aforementioned claim described device one of at least, it is characterized in that the conduction of leading to negative electrode connects screw or bolt that (38,40) particularly preferably are made of brass.

7. by aforementioned claim described device one of at least, it is characterized in that conduction connects (38,40) and launches envelope, with corresponding and coaxial with it distribution of the circumference geometry of target electrode (16).

By aforementioned claim one of at least described device it is characterized in that conduction connects the envelope that (38,40) launch the quadrangle geometry, wherein, each limit between connecting along conduction form identical or essentially identical distance (b, d).

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