HU207605B - Penning spray source having modified magnet arrangement - Google Patents

Abstract

A new magnet element is prepd. by placing concentric circles of magnets of different dias. along the longitudinal axis.(Dwg.0/0)

Description

The present invention relates to a modified magnetized Penning nebulizer source having a magnet system used and trained in accordance with the present invention, which shapes the plasma so that its height above the target is substantially reduced.

It is an object of the present invention to provide new magnet elements for the shape of the central magnet as well as for the positive influence of the magnetic field.

It is known that, in the vacuum-thin-film technique, Penning atomization, known as magnetron proliferation in Anglo-Saxon literature, has become extremely widespread in the last 10 years.

Its spread has affected virtually every industry, from the mechanical engineering to the food industry. Because of this widespread demand, there are increasing demands on Penning spraying.

Penning spraying was first described in U.S. Patent No. 3,656,093. The patent discloses a Penning atomization source, a plasma magnetron, which has a rectangular shape and uses a horseshoe magnet around its circumference. Above the horseshoe magnet is a target on which a cooled copper plate is soldered.

The horseshoe-shaped magnet generates a very small area of plasma, and therefore the wear on the target is very small. The present invention improves upon this by placing, outside the source, electromagnetic coils, which are controlled by alternating current, which causes the small-scale plasma formed to oscillate above the target.

It is known that electric and magnetic fields perpendicular to each other are required to produce a Penning discharge in a pressure range of 0.4 to 4 Pa. The electric field is excited at a voltage of 300 to 800 volts, and the magnet is usually produced with permanent magnets.

In the case of state-of-the-art Penning nebulizer spinners, the material of permanent magnets is more recently cobalt-samarium alloy, which is very expensive.

Because of this fact, in a state of the art Penning atomization source, it is desirable to design the magnet circuit in such a way that a minimum amount of magnetic material is used to provide the solution while providing optimum atomization conditions.

The magnitude of the magnetic field required to generate the discharge is inversely proportional to the geometric size of the plasma. The mean value is 0.03-0.05 T.

It is well known in practice for Penning atomization sources that permanent magnets cannot ensure that the force fields of the magnet are parallel to the entire surface of the material to be atomized, i.e. the target. The disadvantage of this fact is that the dusting of the material is not uniform.

The shape of the wear profile formed during the spraying process determines the percentage of target material that can be sprayed. This is called target utilization in the literature. As the target material is very expensive, there is a strong demand from both manufacturers and users for the development of a nebulizer with a better target utilization value.

In practice, the target utilization of the Penning nebulizer sources, i.e. the ratio of the mass of the target used and the mass of the new target, does not exceed 35%.

For the sake of clarity, Figure 1 schematically illustrates the arrangement of a Penning atomizer source magnet of the LEYBOLD PK 150 type.

As can be seen from the above figure, the central magnet (2) is mounted in the center of the magnetic conductor (4), the magnets being located in the circumference (3).

The figure shows the utilized magnetic force lines (5) and the scattered magnetic force lines (6) from this magnet arrangement. Referring to the figure, magnetic portions saturated by the scattered space are shown.

The magnet parts in the saturation (14) do not play a role in the formation of the magnetic field and are therefore ineffective.

Another problem is the radial running of the magnetic field. The condition of Penning discharge over the entire surface of target (7) would only be met if the magnetic field were parallel to target surface (7) at each point of target (7), because of the equipotential nature of the plasma formed above target (7). is substantially perpendicular to the target surface (7).

The entire electric field is practically concentrated on the cathode portion, which is 1-3 mm here, i.e. the target (7) is considered to be the cathode and the plasma is the anode. The formation of parallel magnetic force lines over the entire target surface (7) cannot be ensured by permanent magnets, but can only be approximated.

In the conventional Penning atomization source (1) outlined in Figure 1, the field lines - which are parallel to it in a very small region of the target surface (7) - result in significant atomization only where the parallel condition occurs.

The abrasion profile (8) formed by such a magnetic arrangement is shown in Figure 1a. The figure clearly shows that in this case the target utilization does not exceed 35%.

Based on the above reasons, it is clear that the current arrangement of the Penning atomization sprays currently in operation cannot increase the value of the target utilization. In our observation, there is a desire among users that, due to the high cost of the materials used, a Penning nebulizer source is needed which is capable of increasing the efficiency of atomization.

This endeavor is satisfied by our invention. It is therefore an object of the present invention to provide a new Penning nebulizer source that has a much better target utilization than known solutions.

It is a further object of the present invention to use only very low-weight magnet materials from highly expensive alloy materials used in magnets, while providing optimum atomization conditions.

The invention is based on the known physical fact that the direction of magnetic force lines can be influenced by magnetic conductors or the shape of magnetic conductors.

HU 207 605 Β

It follows from the above physical fact that the objective can only be achieved by applying a new arrangement to the known magnet arrangements and also by changing the shape of the magnets.

Accordingly, the present invention relates to a modified magnetized Penning nebulizer source having a magnet system used and trained in accordance with the present invention which shapes the plasma in such a way that its extent at the height above the target is substantially reduced.

It is an object of the present invention to provide new magnet elements for the shape of the central magnet as well as for the positive influence of the magnetic field.

The object of the present invention may be achieved by an arrangement in which two or more central magnets of different diameters and diameters are arranged in concentric circles superimposed on each other in a concentric circle from the axis of magnetic conductivity of a circular, polygonal, rounded oval, or different radially rounded circumferences. the pole magnets are fastened along the same magnetic conductor circumference, and the tabs are fixed on the surface of the pole studs towards the target.

The magnet arrangement according to the invention is illustrated in detail in the following figures:

Figure 1 illustrates the arrangement of a conventional Penning atomizer source magnet.

Figure 1a is a sectional view of the target wear of a conventional Penning atomizer source.

Fig. 2 is a magnetic arrangement according to an embodiment of the invention, which includes the poles (9) having central magnets of different diameters (12) and a tab (10).

Figure 2a is a sectional view of the target wear of the Penning atomizer source according to the invention.

Figure 3 is another embodiment of the Penning atomizer source of the present invention, in which the flange magnets (13) are disposed.

The modified magnetization Penning nebulizer source of the present invention may be implemented by a magnet arrangement in which concentric circles are superimposed on each other in a circular or polar sequence 12 with concentric circles superimposed on each other in a circular, polygonal, rounded oval, or different radially rounded circumference (4). ) with a central magnet of different diameters.

Along the periphery of the same magnetic conductor (4), tabs (10) are secured to the target flange (7) of the pole pieces (9).

The modified arrangement of the Penning nebulizer source according to the present invention and the magnetization over the tag (7) provided therewith results in a significant change in the shape of the plasma relative to the known magnetic arrangement Penning nebulizer source shown in FIG.

In the conventional magnet arrangement, the plasma is dome-shaped above the target surface (7), while in the magnet arrangement according to the invention, it has the correct torus shape.

Its elevation is significantly smaller, which gives the following benefits:

1. The larger area of the cathode is pulverized and the target utilization is significantly better.

2. The target (7) to be used can be placed much closer without damaging it. Therefore, the build speed of the layer is higher, so the layer is formed in less time.

3. The use of central magnets (12) of different diameters results in significant amounts of magnetic material savings.

Conveniently, a pole piece (9) is used to change the direction of the magnetic field. The pole piece (9) ensures that the field force lines exit at the edges of the Penning atomizer source (11) with a modified magnet arrangement parallel to the target surface (7), thereby practically improving the wear profile (8) of the target (7). utilization is also improving.

An important part of the pole piece (9) is the tab (10). The function of the tab (10) is primarily to provide the initial direction of the magnetic field. By using the pole piece (9), the target utilization is significantly increased, as evidenced by the wear profile (8) shown in Figure 2a. It was a fundamental aspect of our improved magnet design that we reduce the significant saturation effect of the scattered magnetic force lines (6).

The detrimental effect of the saturation effect is that it disables a significant portion of the central magnet (2), which makes some of the central magnet (2) redundant, that is to say, these magnetic portions (14) do not exist. In addition, if these excess magnetic portions (14) are omitted, a magnetic field parallel to the target surface (7) of the present invention can be practically created by the conical central magnet (2).

The manufacture of a conical (2) central magnet is in practice expensive. The performance of the conical central magnet (2) is well approximated by the central magnets (12) of different diameters when stacked stepwise.

However, the production of central magnets (12) of different diameters is less expensive and thus saves the cost of the device. If the conical magnet (2) is used, its tip is positioned in the direction of the target (7).

A further embodiment of the modified Penning nebulizer source according to the invention may be provided when opposite magnets (13) of opposite polarity are disposed along the circular circumference of the magnetic conductor (4). By using the rim magnets (13), a significant reduction in the operating pressure of the Penning nebulizer source can be achieved by using argon or other working gas.

This reduction is accomplished by the fact that the edge magnets (13) significantly increase the magnetic field above the target (7), that is, the utilized magnetic force lines (5) prevail.

In Figure 1, the conventional Penning atomizer source (1) and the Penning atomizer source (4) of the invention shown in Figure 2 are magnetic

EN 207 605 Β conductor (16) has a cooling inlet and (17) a cooling outlet and target (7) has a power supply (15). The magnets (1) are mounted on the periphery (3) of the magnetic conductor (4) of the conventional Penning atomizer source (4).

The modified magnetization Penning atomizer source we have developed has many advantages over known devices of the same type. One of the most important advantages is that the design of the magnet system allows the plasma to be as close as possible to the larger surface of the target, causing the larger surface of the target to be pulverized and the target utilization to be much higher.

Another important advantage is that the application of the magnet system increases the build speed of the layer so that the desired layer thickness can be achieved in less time.

A further advantage is that, using central magnets of different diameters, a minimum amount of magnetic material is used while providing optimum atomization conditions. This saves significant amounts of very expensive magnets.

Claims (3)

1. A modified magnetized Penning nebulizer source comprising a target cooling system, an equip or radio frequency power supply system, a central magnet, a magnetic conductor, a target having an arrangement in which the magnet of the modified Penning nebulizer source is centered around the periphery and circumferentially circumferentially. they are mounted, the target is placed above the magnet system thus formed, the cooling system is attached to the magnet guides and the DC or RF power source is assigned to the target, characterized in that the circular magnetic, polygonal, rounded oval or different radially rounded magnetic a central magnet (12) of the same polarity, two or more but with different diameters, being stepped over each other in concentric circles from the axis of symmetry of the conductor (4), and the same magnet along the perimeter of the conductor (4) are fixed the pole lugs (9) and the tabs (10) are fixed on the surface of the pole lugs (9) towards the target (7). Penning atomizer source according to claim 1, characterized in that opposite magnets (13) of opposite polarity are disposed along the circular circumference of the magnetic conductor (4). The Penning nebulizer source according to claim 1 or 2, characterized in that the central magnet (2) has a cone shape with its apex disposed in the direction of the target (7).