EP1488445A2

EP1488445A2 - Tube magnetron

Info

Publication number: EP1488445A2
Application number: EP03727150A
Authority: EP
Inventors: Wolfgang Erbkamm; Hans-Christian Hecht
Original assignee: Von Ardenne Anlagentechnik GmbH
Current assignee: Von Ardenne Anlagentechnik GmbH
Priority date: 2002-03-22
Filing date: 2003-03-24
Publication date: 2004-12-22
Also published as: US20050145488A1; WO2003081634A3; WO2003081634A2; DE10213043B4; DE10213043A1; AU2003233915A1

Abstract

The invention relates to a tube magnetron in a vacuum coating plant, provided with a hollow rotating tube target arrangement and a magnet system, comprising two magnetic field maxima in cross-section arranged in the axial longitudinal direction of the tube target arrangement and therein. The magnetic field passes through the tube target arrangement and the tube target arrangement comprises target plates running longitudinally which are fixed to a target support. The aim of the invention is to achieve an improved process uniformity as an essential condition for a high layer quality on the substrate, in particular on the use of target plates made from ceramics for example, ITO, zinc oxide, silicon and other ceramic, ceramic-like and/or high-melting materials. Said aim is achieved whereby the target plates are arranged adjacent to each other to form a polygon in cross-section.

Description

tubular magnetron

The invention relates to a tubular magnetron of a vacuum coating system, which is provided with a hollow, rotatably mounted tubular target arrangement and with a magnet system. The magnet system has two magnetic field maxima in cross section and is arranged in the axial longitudinal extent of the tube target arrangement and in the interior thereof, the magnetic field penetrating the tube target arrangement. The tube target arrangement has elongated target plates which are attached to a target carrier.

The magnetic field maximum specified here and below is the maximum of the tangentially oriented magnetic field component on the target surface.

Tubular magnetrons of a general type have long been known for use in vacuum coating systems for coating various large-area substrates with different layer materials. They are characterized by a high utilization rate of the target material and a long target life. A tubular magnetron is described in German patent specification DD 217964 A3. Uniform erosion of the sputtering material on the surface of the tube target is achieved by uniform rotation of the tube target. The tube target consists entirely of the material to be sputtered, such as aluminum or titanium. The target cooling in the interior of the tube target is much more effective than with flat targets due to the more favorable heat transfer in the tube, which increases the performance in relation to the coating. rate compared to the flat targets. In the application by the applicant, solid tube targets made of copper and titanium are also known.

Another tubular magnetron is known from US 4,356,073. In this case, tube targets are used which consist of a carrier tube and a layer of the sputtering material applied all round. This layer consists primarily of metallic sputtering material and is mainly applied by plasma spraying.

No. 4,443,318 describes the most obvious prior art, in which a rotating magnetron is equipped with a tube target which has a large number of individual target strips with the applied sputter material, attached to a carrier tube. The target strips are located in individual grooves of the support tube and are pressed against the support tube by clamping strips (claws) that are screwed onto the support tube. This design allows the use of target materials produced in plate form on the surface of tubular targets. This has the advantage of cheaper and wider range of use of different sputtering materials, because depending on the material, the production of plate material is sometimes easier and more economical than the use of solid material tube targets and the plasma spraying process, and in addition only the production in plate form is partially suitable, such as for ceramic sputtering materials with their great hardness and brittleness.

The application of ceramic sputtering material to the surface of a tube target is difficult in the plasma spraying process, since it does not achieve the required material density and material homogeneity of the ceramic material connections. Minor structural and alloy deviations with certain ceramic sputter layers, such as with ITO (indium Tin oxide alloy) or silicon oxide lead to process irregularities. Similarly, solid material tube targets made of ceramic sputter material with the required properties are not known in the current state of the art. The ceramic material sintered in the high-pressure pressing process has a high block density and hardness, which means that this material cannot be processed arbitrarily. The plate shape is therefore a preferred manufacturing form for ceramic sputtering materials.

On the known tube targets covered with target plates, however, it is disadvantageous that, due to the tangential support of the flat plates, there is a different radial distance between the target plate surface and the axis of rotation of the tube target and, furthermore, surface areas without target material occur due to the holding mechanisms of the target plates (claws), which creates a polygon Tube target surface with inhomogeneous sections is created. This surface of the tube target leads in the coating process during the turning process of the tube target due to the fixed magnetic fields to considerable fluctuations in the magnetic field effect and thus the sputtering rate and subsequently to fluctuations in the process parameters of the plasma. The process uniformity as an essential prerequisite for the layer quality on the substrate is disturbed.

The object on which the invention is based is that when using target plates on tubular targets, in particular target plates made of ceramics, for example made of ITO, zinc oxide, silicon and other ceramic, ceramic-like and / or high-melting material, improved process uniformity is an essential prerequisite for high layer quality the substrate is to be achieved. The coating quality when using the tube targets with target plates should be matched to the coating quality when using tube targets with applied sputter material or consisting of solid material in order to be more variable and To enable cost-effective coating processes when using tube targets with the same quality.

This object is achieved in that the target plates are arranged adjacent to one another in cross section, forming a polygon. This prevents surface areas from appearing as inhomogeneous sections on the tube targets without target material. This significantly reduces the sudden fluctuations in the magnetic field strength and the sputtering rate, which are generated by the alternating traversing of the target plate surfaces and the interstices free of sputtering material by the magnetic fields of the magnet system.

In a favorable embodiment of the invention, the width and number of the target plates is chosen such that an angle, which is enclosed by two imaginary radial lines running through a corner of two adjacent corners of the polygon, becomes an angle β, that of two through the magnetic field maxi - Including the imaginary radial lines, is related to

ß = (n + 0.5) -α with (n = 0, 1, 2, 3, 4 ...).

It is thereby achieved that the distance of each corner of the polygon from the central longitudinal line of a target plate is approximately equal to the distance of the magnetic field maxima in the area of the target plate surface.

A corner creates a comparatively low sputter rate in the magnetic field maximum and a center of the area - because of its greater proximity to the magnet system - a comparatively high sputter rate. Due to the configuration, a corner passes through one magnetic field maximum, while a center of the surface passes through the other magnetic field maximum. This results in a high sputter rate paired with a low sputter rate, in total an average sputter rate. other sections behave in the same way the polygon to each other. This compensates for peaks in the sputtering rates in total and further reduces the fluctuations in the sputtering rate, which are generated by the polygonal tube target surface, despite the full-surface arrangement of the target plates.

In other words, when passing through a point on the target surface with the largest tube target radius "polygon corner" due to the magnetic field, the magnetic field effect on the plasma space weakens and the sputter rate is reduced to a minimum, whereas passing through the point of the target surface with the smallest tube target radius ("polygon sink ") leads to an increase in the magnetic field effect and the sputter rate increases to a maximum. This swelling and swelling of the sputter rate when passing through the magnetic fields is preferably, preferably by the repetitive positioning of a" polygon tip "and a" polygon sink "simultaneously in areas of the magnetic field at its two maxima, depending on the distance between the magnetic field maxima and the relative width of the target plates, the longitudinal edge of the plate forming the polygon tips and the central longitudinal line forming the polygon sinks ger target plates can be combined. This arrangement achieves the effect of damping the vibration behavior of the sputter rate and thus process uniformity of a new quality.

It is particularly favorable to choose the width and number of target plates such that ß = 1, 5 •.

For polygons with different number of corners, the following angles of the magnetic field maxima result:

for a hexagonal polygon: ß = 90 ° for an octagonal polygon: ß = 67.5 ° for a 10-sided polygon: ß = 54 ° for a 12-sided polygon: ß = 45 ° etc.

With these angles, widths of the target plates are possible that can be mastered technologically.

In a favorable embodiment of the invention, the target plates are glued or bonded onto the target carrier. This technology facilitates the adjacent arrangement of the target plates on the support tube and avoids fastening aids that lead to inhomogeneous surface design of the tube target.

In an expedient embodiment of the invention, the target plates consist of ceramics e.g. from ITO, zinc oxide, silicon and from other ceramic, ceramic-like and / or refractory material, which are difficult to apply to a tube target by other methods.

In a further embodiment of the invention, the tube target can be rotated at a speed of 1 s ^"1 to 2 min ^{" 1} . This means that the speed of the tube target can be optimally aligned to target plates of different widths.

Finally, one use of the invention provides that minimal fluctuations in the plasma or the sputter rate are compensated for by regulating the voltage or by regulating the plasma emission monitor.

The effective compensation of the sputter rate fluctuation by the target plate arrangement according to the invention is further perfected by this regulation.

The invention will be explained in more detail below using an exemplary embodiment. The accompanying drawing shows a cross section through a tube target with the brought target plates and an internal magnet system.

The magnetron is equipped here with a rotating tube target 1, which consists of a tubular target carrier 2, on which a large number of individual elongate plane target plates 3 with applied sputtering material, such as e.g. ITO, zinc oxide, silicon and other ceramic, ceramic-like and / or high-melting material, are glued or bonded adjacent to each other. The tangential support of the flat target plates 3 on the tubular target carrier 2 forms a complete but polygonal target surface with polygon corners 4 and polygon sinks 6 on the tube target 1.

Due to the shape, the plate longitudinal edges 8 of the target plates 3 geometrically form the polygon corners 4 and the central longitudinal axis 9 of the target plates 3 geometrically consider the polygon sinks 6 of the target surface.

In the interior of the tube target 1 is the fixed magnet system 10, which generates a magnetic field with two magnetic field maxima 11 which penetrate the tube target 1 at a distance 12 which is dependent on the design of the magnet system 10. The maximum possible sputter rate is in the core zones of the magnetic field, i.e. H. Reached approximately in the area of the two magnetic field maxima 11, outside of which the sputter rate decreases.

The width 7 of each target plate 3 and the number of target plates 3 is now selected such that an angle α, which is enclosed by two imaginary radial lines 13 and 14 running through a corner of two adjacent corners 4 and 5 of the polygon, becomes one Angle β, which is enclosed by two imaginary radial lines 15 and 16 running through the magnetic field maxima 11, is related to ß = (n + 0.5) -α with n = 1, ie

ß = 1.5 -α

As a result, the distance between each longitudinal edge 8 of the target plates 3 and the central longitudinal axis 9 of the adjacent target plate is approximately equal to the distance between the magnetic field maxima 12 in the region of the target plate surface. These two geometrically relevant points (one polygon corner 4 and one polygon sink 6) are located simultaneously in one of the two magnetic field maxima 11 during the rotation of the tube target 1. The deviations in the sputtering rate cancel each other out due to the different radial distance between the tube target surface and the axis of rotation of the tube target 1 and thus to the fixed magnet system 10 occur. If several magnetic fields are used, the arrangement is to be carried out analogously in such a way that the same number of polygon corners 4 and polygon sinks 6 are in the magnetic field maxima 11 at the same time.

tubular magnetron

LIST OF REFERENCE NUMBERS

Tube target Target carrier Target plate Polygon corner Polygon corner Polygon sink Width of the target plate Longitudinal edge of the target plate Central longitudinal axis of the target plate MagnetSystem Magnetic field maximum Distance of the magnetic field maximums Radial line through a polygon corner Radial line through a polygon corner Radial line through a magnetic field maximum Radial line through a magnetic field maximum

Claims

RohrmagnetronPatentansprüche

1. Rohrmagnetron a vacuum coating system, which is provided with a hollow, rotatably mounted tube target arrangement, and with a magnet system, which has two magnetic field maxima in cross section and which is arranged in the axial longitudinal extent of the tube target arrangement and in the interior thereof, the magnetic field penetrating the tube target arrangement and the tube target arrangement has elongated target plates which are fastened on a target carrier, characterized in that the target plates (3) are arranged adjacent to one another in cross section to form a polygon.

2. tubular magnetron according to claim 1, characterized in that the width and number of the target plates (3) is chosen so that there is an angle α, the two by one corner (4; 5) of two adjacent corners (4; 5) of the imaginary radial lines (13; 14) running at an angle ß, which is enclosed by two imaginary radial lines (15; 16) running through the magnetic field maxima (11)

ß = (n + 0, 5) • α with (n = 0, 1, 2, 3, 4 ...).

3. tubular magnetron according to claim 2, characterized in that ß = 1, 5 •.

4. tubular magnetron according to any one of claims 1 to 3, characterized in that the target plates (3) on the target carrier (2) are glued or bonded.

5. tubular magnetron according to claims 1 to 4, characterized in that the target plates (3) made of ceramics e.g. consist of ITO zinc oxide, silicon and other ceramic, ceramic-like and / or refractory material.

6. tubular magnetron according to claims 1 to 5, characterized in that the tubular target (1) with a speed of 1 s ^"1 to 2 min ^{" 1 is} rotatable.

7. Use of a tubular magnetron according to one of claims 1 to 6, characterized in that a compensation of minimal fluctuations in the plasma or the sputtering rate takes place by means of a regulation of the voltage or by means of a plasma emission monitor regulation.