METHODS OF AND APPARATUS FOR MAGNETRON SPUTTERING

Abstract

In a magnetron sputtering reaction space a magnetron magnetic field is generated. A further magnetic field is generated in the reaction space whereby a resultant magnetic field has a directional component parallel to a target plane which is larger than the directional component of the magnetron magnetic field parallel to the target plane in the reaction space.

Claims

1. A sputtering apparatus comprising: a vacuum enclosure and therein: a substrate holder defining a substrate plane and tailored to hold a two-dimensionally extended substrate having a surface to be sputter coated facing a reaction space; a target of ferromagnetic material mounted to a target holder and extending along a target plane and having a sputter surface and a back surface; a magnetron magnet-dipole arrangement generating in said reaction space a magnetron magnetic field and comprising, seen in a direction towards said sputter surface, a first outer pole surface and a first inner pole surface, said first outer pole surface forming a closed loop around said first inner pole surface and along said sputter surface, said first outer pole surface being of a first magnetic polarity, said first inner pole surface being of a second magnetic polarity; a further magnet-dipole arrangement generating in said reaction space a further magnetic field and having at least one second outer pole surface and at least one second inner pole surface, and wherein, seen in direction towards said sputter surface, said at least one second inner pole surface is within said loop of said first outer pole surface and said at least one second outer pole surface is outside a periphery of a substrate held on said substrate holder, said second outer pole surface having said first magnetic polarity, said second inner pole surface having said second magnetic polarity; and a resultant magnetic field, resulting from said magnetron magnetic field and from said further magnetic field and along at least a predominant part of said surface of said substrate held on said substrate holder, being unidirectional.

2. The sputtering apparatus of claim 1, wherein said second outer pole surface is located outside the periphery of said target, seen in direction towards said sputter surface.

3. The sputtering apparatus of claim 1, wherein said magnetron magnet-dipole arrangement and said further magnet-dipole arrangement are tailored so that field lines of said magnetron magnetic field generated by said magnetron magnet-dipole arrangement and field lines of said further magnetic field generated by said further magnet-dipole arrangement are mutually parallel along at least a part of said closed loop and as seen in direction towards said sputter surface.

4. The sputtering apparatus according to claim 1, wherein said first outer pole surface is a part of said sputter surface.

5. The sputtering apparatus according to claim 1, said at least one second inner pole surface being a part of said sputter surface.

6. The sputtering apparatus according to claim 1, said at least one second inner pole surface being distant from said sputter surface.

7. The sputtering apparatus according to claim 6, said at least one second inner pole surface being located opposite said sputter surface with respect to said substrate plane.

8. The sputtering apparatus of claim 1, wherein said at least one second outer pole surface, seen parallel to said target plane, is in at least one of the following positions: opposite to said target plane with respect to said substrate plane; aligned with said substrate plane; between said target plane and said substrate plane and closer to said substrate plane than to said target plane; between said target plane and said substrate plane and more distant from said substrate plane than from said target plane; between said target plane and said substrate plane and equidistant from said substrate plane and from said target plane; aligned with said target plane; opposite said substrate plane with respect to said target plane.

9. The sputtering apparatus of claim 1, wherein said first inner pole surface is a further closed loop seen in direction towards said sputter surface.

10. The sputtering apparatus of claim 9, wherein said second inner pole surface is within said further closed loop seen in direction towards said sputter surface.

11. The sputtering apparatus of claims 1, wherein at least parts of said first and of said second inner pole surfaces are overlapping, seen in direction towards said sputter surface.

12. The sputtering apparatus of claim 1, said loop of said first outer pole surface having a maximum loop diameter, said at least one second outer pole surface comprising a bar shaped arrangement of at least one second pole surface on one side of said maximum diameter and a further bar shaped arrangement of at least one second pole surface on the other side of said maximum diameter, seen in a direction towards said sputter surface.

13. The sputtering apparatus of claim 12 comprising, seen in a direction towards said sputter surface, a first leg of said first outer pole surface extending on one side of said maximum diameter along a first linear locus and a second leg of said first outer pole surface extending on the other side of said maximum diameter along a second linear locus, said one bar shaped arrangement extending along said first leg and said further bar shaped arrangement extending along said second leg, seen in a direction towards said sputter surface.

14. The sputtering apparatus of claim 13, wherein said first and second legs extend linearly, seen in a direction towards said sputter surface.

15. The sputtering apparatus of claim 14, wherein said first and second legs are parallel to each other, seen in a direction towards said sputter surface.

16. The sputtering apparatus of claim 12, wherein said bar shaped arrangement and said further bar shaped arrangement extend along respective linear loci, seen in a direction towards said sputter surface.

17. The sputtering apparatus of claim 16, wherein said bar shaped arrangement and said further bar shaped arrangement extend linearly, seen in a direction towards said sputter surface.

18. The sputtering apparatus of claim 13, wherein said bar shaped arrangement and said further bar shaped arrangement extend with respective constant spacing aside said respective legs , seen in a direction towards said sputter surface.

19. The sputtering apparatus of claim 1, wherein a part of a vacuum-exposed surface of said vacuum enclosure is said at least one second outer pole surface or a vacuum exposed surface of a part mounted to said vacuum enclosure is said at least one second outer pole surface.

20. The sputtering apparatus of claim 1, comprising at least one further vacuum treatment apparatus, the substrate holder on one hand and the target holder and as well the at least one further vacuum treatment apparatus on the other hand, are drivingly movable relatively to each other, passing the substrate holder across the sputter surface and passing the substrate holder to or from the at least one further vacuum treatment apparatus.

21. The sputtering apparatus of claim 20, comprising more than one of said substrate holders movable relative to said sputter surface and to the at least one further vacuum treatment apparatus.

22. The sputtering apparatus of claim 20, at least one of said further vacuum treatment apparatus is a sputtering apparatus comprising: a second vacuum enclosure and therein: a second substrate holder defining a second substrate plane and tailored to hold a two-dimensionally extended substrate having a surface to be sputter coated facing a reaction space; a second target of ferromagnetic material mounted to a second target holder and extending along a target plane and having a sputter surface and a back surface; a second magnetron magnet-dipole arrangement generating in said reaction space a magnetron magnetic field and comprising, seen in a direction towards said sputter surface, a first outer pole surface and a first inner pole surface, said first outer pole surface forming a closed loop around said first inner pole surface and along said sputter surface, said first outer pole surface being of a third magnetic polarity, said first inner pole surface being of a fourth magnetic polarity; a further magnet-dipole arrangement generating in said reaction space a further magnetic field and having at least one second outer pole surface and at least one second inner pole surface, and wherein, seen in direction towards said sputter surface, said at least one second inner pole surface is within said loop of said first outer pole surface and said at least one second outer pole surface is outside a periphery of a substrate held on said second substrate holder, said second outer pole surface having said third magnetic polarity, said second inner pole surface having said fourth magnetic polarity; and a resultant magnetic field, resulting from said magnetron magnetic field and from said further magnetic field and along at least a predominant part of said surface of said substrate held on said second substrate holder, being unidirectional.

23. The sputtering apparatus of claim 20, wherein said resultant magnetic unidirectional field extends in direction of a directional axis over a predominant part of said sputter surface, and said relative movement of said substrate holder is controlled in such a manner, that said substrate holder passes said sputter surface at a constant angular orientation with respect to said directional axis.

24. The sputtering apparatus of claim 23, wherein said substrate holder is drivingly relatively rotatable around a rotation axis which is remote from said substrate holder.

25. The sputtering apparatus of claim 24, wherein said rotation axis intersects normal on said substrate planes at angles greater than or equal to 0° and less than or equal to 45°.

26. The sputtering apparatus of claim 25, wherein said angles are 0°, said rotation axis thus being perpendicular to said substrate planes.

27. The sputtering apparatus of claim 24, wherein said rotation axis intersects normal on said substrate planes at angles greater than or equal to 45° and less than or equal to 90°.

28. The sputtering apparatus of claim 27, wherein said angles are 90° said rotation axis thus being parallel to said substrate planes.

Description

[0132] The invention shall be further exemplified with the help of figures. The figures show:

[0133] FIG. 1: A most simplified vacuum enclosure with a target and pole surfaces, so as to define the term “pole surfaces”;

[0134] FIG. 2: Schematically and heuristically the generic approach according to the methods and apparatus of the present invention in a lateral view;

[0135] FIG. 3: In a representation in analogy to that of FIG. 2, schematically and simplified, different embodiments of the apparatus or different variants of the methods according to the invention with respect of generating the further magnetic field of FIG. 2;

[0136] FIG. 4: In a representation in analogy to that of FIG. 3 not showing the target, an embodiment or a variant according to the invention with respect of generating the further magnetic field adjacent the substrate;

[0137] FIG. 5: in a schematic and simplified top view a mutual positioning of the pole surfaces at an embodiment of the apparatus or at a variant of the methods according to the invention;

[0138] FIG. 6: in a schematic and simplified top view in analogy to that of FIG. 5, a mutual positioning of the pole surfaces at an embodiment of the apparatus or at a variant of the methods according to the invention;

[0139] FIG. 7: in a schematic and simplified top view in analogy to that of FIG. 5 or FIG. 6 a mutual positioning of the pole surfaces at an embodiment of the apparatus or at a variant of the methods according to the invention especially with an eye on influencing layer deposition by the resulting magnetic field;

[0140] FIG. 8: qualitatively the distribution of magnetic field strengths in dependency from the spacing from the sputter surface towards the substrate for exploiting the resultant magnetic field as an alignment magnetic field.

[0141] FIG. 9: in a top view, schematically and heuristically, aligning the magnetic anisotropy of a ferromagnetic layer as realized by embodiments and variants of the present invention;

[0142] FIG. 10: in top view, schematically and simplified, mutual positions and shapes of pole surfaces of an embodiment and variant of the invention;

[0143] FIG. 11: in a representation in analogy to that of FIG. 10 schematically and simplified mutual positions and shapes of pole surfaces of an embodiment and variant of the invention;

[0144] FIG. 12: in a lateral view, simplified and schematically an embodiment and variant of the invention;

[0145] FIG. 13: simplified and schematically, in top view, the mutual positions and shapes of the pole surfaces of the embodiment and variant of FIG. 12;

[0146] FIG. 14: An embodiment or variant of the invention in which multiple substrates are moved passing at least one sputtering apparatus according to the invention;

[0147] FIG. 15: An embodiment or variant of the invention in which multiple substrates are moved passing at least one sputtering apparatus according to the invention;

[0148] FIG. 16: schematically and simplified, in a top view, a vacuum treatment apparatus comprising at least one sputtering apparatus according to the invention and performing a method according to the invention;

[0149] FIG. 17: schematically and simplified, in a lateral view, a vacuum treatment apparatus comprising at least one sputtering apparatus according to the invention and performing a method according to the invention;

[0150] FIG. 18: schematically the spacial orientation of a substrate to be maintained with respect to the resultant magnetic field, so as to homogeneously align the magnetic anisotropy;

[0151] FIG. 19: schematically and simplified, in a top view, an orientation control for the substrates at an apparatus according to FIG. 17 in functional-block representation.

[0152] FIG. 2 shows schematically and heuristically i.e. in a non-scientific manner, the generic approach according to the method and apparatus of the present invention. Within the vacuum enclosure or recipient (not shown in FIG. 2) there is provided a target 1, mounted to a target holder 3. As schematically shown by the electric supply source 5 and anodes 7, the target 1 is electrically operated as a cathode. The target holder 3 defines a target plane 9 as a locus along which the target 1, mounted to the target holder 3, extends. The surface of target 1 sputtered off is the sputter surface 11.

[0153] A substrate 13 has a surface 15 to be sputter coated with a material comprising the sputtered off material from the target 1. The substrate 13 is mounted to a substrate holder 17 which defines a substrate plane 19, as a locus along which the substrate 13, held by the substrate holder 17, extends.

[0154] As perfectly known to the skilled artisan familiar with magnetron sputtering, there is generated along the sputter surface 11 and in a reaction space I a magnetron magnetic field B.sub.m. The magnetron magnetic field B.sub.m, as shown by its magnetic field lines, emanates from a first outer pole surface 20 shown by thickened lines. The first outer pole surface loops along the sputter surface 11 as seen in a direction S1 towards the sputter surface 11, i.e. in a top view towards the target 1.

[0155] The magnetron magnetic field B.sub.m impinges on one or more than one first inner pole surfaces 22 also shown by thickened lines in FIG. 2. The first inner pole surface 22 may be a single pole surface as shown in dash lines.

[0156] In FIG. 2 a stationary magnetic dipole arrangement 24 is schematically shown only at the right-hand side of the magnetron magnetic field B.sub.m-loop for clearness sake.

[0157] Seen in the direction S1 i.e. towards the sputter surface 11 or the target plane 9, the first outer pole surface 20 forms a closed loop around the one or more than one first inner pole surfaces 22. In FIG. 2 the first outer pole surface 20 has the magnetic N-polarity, whereas the at least one first inner pole surface 22 has S magnetic polarity. These polarities may be inversed.

[0158] The direction of the magnetron magnetic field B.sub.m may be considered in components parallel to the target plane 9, B.sub.mx, and in components, B.sub.mz, perpendicularly thereto.

[0159] It is perfectly known to the skilled artisan that the component B.sub.mx govern the electron trap effect of the magnetron and thus the respective plasma density adjacent to the sputter surface 11 and thus the respectively formed race track, i.e. the erosion profile in the sputter surface 11. The more pronounced these components B.sub.mx are along the sputter surface 11, the larger will be the race track and the better will be the exploitation of the target material.

[0160] To improve the effect of the magnetron magnetic field B.sub.m and according to the invention there is generated a further magnetic field B.sub.a. As schematically shown in FIG. 2 this further magnetic field B.sub.a is generated in the reaction space I so that the resulting magnetic field B.sub.r considered at a locus in the reaction space I and resulting from superposition of B.sub.m and B.sub.a at said locus has larger components B, parallel to the target plane 9 than the component B.sub.mx at that locus. As perfectly clear from FIG. 2 the further magnetic field B.sub.a must be polarized in a direction equal to the direction of polarization of the magnetron magnetic field B.sub.m in the direction x to achieve the addressed improvement. At every locus of the reaction space I where B.sub.a has a non-vanishing directional component B.sub.ax such improvement is achieved and thus along a predominant area of the sputter surface 11.

[0161] So as not to overload FIG. 2, FIGS. 3 and 4 show, in a representation in analogy to that of FIG. 2 different possibilities to generate the further magnetic field B.sub.a.

[0162] The magnetic polarities of all pole surfaces which will be addressed are based on the polarities of the pole surfaces 20 and 22 for the magnetron magnetic field B.sub.m according to FIG. 2. All these magnetic polarities may be commonly inversed.

[0163] According to FIG. 3, the further magnetic field B.sub.a is generated between a second inner pole surface 30 and a second outer pole surface 32.

[0164] The second inner pole surface 30 is located opposite to the sputter surface 11 with respect to the substrate plane 19, e.g. behind the substrate 13. The second inner pole surface 30 is further aligned with a central area of the substrate holder 17 as will be discussed later and in any case inside the loop of the first outer pole surface 20 (see FIG. 2) seen in top view—S1—towards the target 1. In analogy to the first inner pole surface 22 also the second inner pole surface 30 may be subdivided in more than one respective pole surface areas.

[0165] The second outer pole surface 32 is located outside the loop of the first outer pole surface 20 (see FIG. 2) and again seen in direction S1. According to FIG. 3 and seen in a direction y parallel to the target plane 9 and thus in direction of propagation of the magnetron magnetic field loop, as shown by S2, the second outer pole surface or surfaces 32 may be located: [0166] (a) opposite to the sputter surface 11 or the target plane 9 with respect to the substrate plane 19; [0167] (b) aligned with the substrate plane 19; [0168] (c) between the substrate plane 19 and the target plane 9 and closer to the substrate plane 19 than to the target plane 9; [0169] (d) centered with respect to the substrate plane 19 and the target plane 9 and thus equidistant from the substrate plane 19 and the target plane 9; [0170] (e) between the substrate plane 19 and the target plane 9 and closer to the target plane 9 than to the substrate plane 19; [0171] (f) aligned with the target plane 9; [0172] (g) opposite to the substrate plane 19 with respect to the sputter plane 9.

[0173] As addressed above the one or more than one second outer pole surfaces 32 are nevertheless outside the loop of the first outer pole surface 20, seen in direction S 1.

[0174] Still seen in this direction 51, the second outer pole surface 32 may form a loop along the first, looping outer pole surface 20 (see FIG. 2): In this case there is provided a single second outer pole surface 32.

[0175] Alternatively, or possibly additionally, two or more than two distinct second outer pole surfaces 32 may be provided along the loop of the first outer pole surface 20.

[0176] Please note, that in FIG. 3 the second outer pole surfaces 32 at the different possible locations (a) to (g) are not shown for the right hand-side part of the further magnetic field B.sub.a. Please further note that under a general aspect, the positions as shown by (a) to (g) of a single second outer pole surface 32 or of more than one second outer pole surfaces 32 may vary along the loop of the first outer pole surface 20 i.e. there may be provided second outer pole surfaces or a single second outer pole surface at different of the positions (a) to (g).

[0177] In FIG. 3 a magnetic dipole arrangement generating the further magnetic field B.sub.a is shown at 34.

[0178] The pole surfaces 32 and 30 are again shown schematically in FIG. 3 by thickened lines which is also valid for representation of pole surfaces in following figures.

[0179] An alternative possibility to tailor the further magnetic field B.sub.a is shown in FIG. 3 at B.sub.a′ in dash lines. Here the second inner pole surface 30′ is or are provided as a part of the sputter surface 11. Please note that a combination of generating the further magnetic field by B.sub.a and by B.sub.a′ is also possible. In any case the various possibilities (a) to (g) for the second one or more than one second outer pole surfaces 32 are valid irrespective of generating B.sub.a and/or B.sub.a′.

[0180] As apparent, the present invention makes use of a further magnetic field B.sub.a, B.sub.a′, additionally to a magnetron magnetic field B.sub.m, which latter, per se, is commonly known. This necessitates an additional magnetic dipole arrangement as of 34 in FIG. 3. In one variant and embodiment of the invention such additional magnetic dipole arrangement is located outside the wall 2 of the vacuum enclosure 4 (see FIG. 1).

[0181] FIG. 4 shows, in a representation in analogy to that of FIG. 2 or 3, as an example such a variant and embodiment, thereby generating the further magnetic field in the variant B.sub.a, with the second outer pole surface or surfaces 32 in a position according to (a) of FIG. 3. The magnetic dipole arrangement 34 is provided outside the wall 2 of the vacuum enclosure 4. The target holder, the target and the magnetron magnetic field with respective pole surfaces are not shown in FIG. 4.

[0182] The wall 2 of the vacuum enclosure 4 separates sputter processing vacuum from a different gaseous atmosphere U, especially ambient atmosphere. The one or more than one second outer pole surfaces 32 reside on the inner, process-vacuum exposed surface 2.sub.i of the wall 2. The second inner pole surface 30 on that surface 2.sub.i as well. The further magnetic dipole arrangement 34 is located outside the vacuum sputter atmosphere as prevailing in the reaction space I, e.g. in ambient atmosphere.

[0183] The generic concept of providing the magnetic dipole arrangement 34 for the further magnetic field B.sub.a and/or B.sub.a′ separate from the vacuum sputtering atmosphere in the reaction space I may be realized for any variant of generating the further magnetic field B.sub.a, B.sub.a′ according to FIG. 3 and the description thereof.

[0184] The example according to FIG. 4 i.e. having the at least one second outer pole surface 32 as well as the at least one second inner pole surface 30 along the inner surface 2.sub.i of a part of the wall 2 of the vacuum enclosure 4 adjacent to the substrate plane 19, is especially suited if one or more than one substrates 13 with the respective substrate holders 17 are to be moved pass the target 1 as schematically shown by bi-directional or mono-directional arrows M in FIG. 4.

[0185] Up to now we have not finally considered the mutual positioning of the pole surfaces for the magnetron magnetic field B.sub.m and for the further magnetic field B.sub.a, B.sub.a′ as seen in direction S1. In fact, this positioning may be selected substantially independently from the mutual positions of the pole surfaces as seen in direction S2 according to FIG. 3. With respect to the addressed mutual positioning seen in direction S1 we have only described, that the second inner pole surface or surfaces 30 (FIG. 3) should be placed inside the looping first outer pole surface 20 (FIG. 2) and that the at least one second outer pole surface 32 (FIG. 3) should be outside the looping first outer pole surface 20.

[0186] FIG. 5 exemplifies schematically an embodiment of mutual positioning of the pole surfaces, seen in direction S1. The looping first outer pole surface 20, is, as an example, forming a circular loop of magnetic polarity N. Inside the loop of the first outer pole surface 20 the inner pole surface 22 (see FIG. 2) is provided, with magnetic polarity S. In the example of FIG. 5 the one first inner pole surface 22 forms a circular loop, concentric to the loop of the first outer pole surface 20. The second outer pole surface 32 is, in this example looping as well concentrically to and outside the loop of the first outer pole surface 20 thus, in this example, at a constant spacing from the loop of the first outer pole surface 20.

[0187] The at least one second inner pole surface 30 or 30′ (see FIG. 3), here just one second inner pole surface, is positioned inside the loop of the first outer pole surface 20 but, here, at a randomly selected position.

[0188] The directions of the magnetron magnetic field B.sub.m and of the further magnetic field B.sub.a or B.sub.a′ are heuristically represented by their magnetic field lines, seen in direction S1. As may be seen, the magnetron magnetic field—B.sub.m—directions and the directions of the further magnetic field B.sub.a, B.sub.a′ intersect at most loci in the reaction space I seen in direction S1 with a respective variable angle α. Although such a variant or embodiment falls under the generic approach according to the invention, it might be seen that the resultant magnetic field B.sub.r has a direction which is tilted with respect to the propagation direction PR of the magnetron race track.

[0189] Thus, the magnetron effect is on one-hand improved by increasing the magnetic field component parallel to the target plane but is on the other hand disturbed by accelerating electrons away from the magnetron propagation direction PR, out of the magnetron electron trap.

[0190] In a further variant and embodiment of the invention according to FIG. 6 the directions of the magnetron magnetic field B.sub.m and of the further magnetic field B.sub.a, B.sub.a′ are mutually parallel as seen in direction S1. The variant or embodiment of FIG. 6 differs from that of FIG. 5 only in that the at least one second inner pole surface 30, 30′is inside the loop of the first inner pole surface 22. In an alternative embodiment or variant, the first—22—and the second 30, 30′ inner pole surfaces mutually overlap.

[0191] With an eye on FIG. 5, we propose to realize α to be within the limits:

0≤α≤2°.

[0192] As may be seen e.g. from FIGS. 2, 3, 4 the magnetic field B.sub.r resultant from superposition of the magnetron magnetic field B.sub.m and of the further magnetic field B.sub.a, B.sub.a′ is also present along the surface 15 to be sputter-coated of the substrate 13. Thus, additionally to improving magnetron sputtering from the target 1 the methods and apparatus according to the invention may be tailored to specifically influence layer deposition on the surface 15 of the substrate 13 to be sputter-coated.

[0193] As already apparent e.g. from FIG. 3, the influence of the further magnetic field B.sub.a, B.sub.a′ on the resultant magnetic field B.sub.r may be tailored to be more pronounced adjacent to the substrate plane 19 than adjacent to the target plane 9.

[0194] In one variant and embodiment the resultant magnetic field B.sub.r, resulting from superposition of the magnetron magnetic field B.sub.m and of the further magnetic field B.sub.a, B.sub.a′, is exploited to establish i.e. to control the direction of magnetic anisotropy in a ferro magnetic layer as sputter deposited to be unidirectional, at least in a predominant part of the layer extent. In this variant and embodiment, the target 1 mounted or to be mounted on the target holder 1 is of a ferromagnetic material.

[0195] The generic approach of such a variant of the methods and embodiments of the apparatus according to the invention is shown in FIG. 7. This figure shows mutual positions of the pole surfaces seen in direction S1. The shape of the pole surfaces as shown in FIG. 7 is hardly a shape exploited in praxis, but shall show that, according to specific applications, one is largely free to tailor the respective shapes.

[0196] For the respective pole surfaces the same reference numbers are used in FIG. 7 as were used throughout the description to now.

[0197] Generically, the looping first outer pole surface 20 may have a loop shape as needed e.g. for a specific shape of the target 1, of the substrate 13 etc. Accordingly, the first inner pole surface or surfaces 22, as a loop or as an unitary or more than one unitary pole surfaces, is adapted to the specific shape of the loop of the first outer pole surface 20.

[0198] The loop of the first outer pole surface 20 has a maximum diameter D.sub.max.

[0199] On both sides of the maximum diameter D. and outside the loop of the first outer pole surface 20 the second outer pole surface 32 is realized by two or more than two distinct pole surfaces 32a and 32b extending along respective distances along the maximum diameter D.sub.max. The shapes and the respective positions of the distinct second outer pole surfaces 32a and 32b is again selected to achieve a desired resultant magnetic field B.sub.r from the superposition of magnetron magnetic field B.sub.m and of the further magnetic field B.sub.a, B.sub.a′, which may now be said an “alignment magnetic field”.

[0200] With an eye on FIG. 3, for the exploitation of the resultant magnetic field B.sub.r for aligning the direction of magnetic anisotropy along a ferromagnetic material layer deposited by the sputtering on the substrate 13, the substrate 13 and especially its surface 15 to be sputter coated is located in the rather far field area with respect to the magnetron magnetic field B.sub.m and rather in the near field area of the further magnetic field B.sub.a, B.sub.a′. This is schematically and qualitatively represented in FIG. 8. The d coordinate addresses the distance from the sputter surface 11 of target 1 in vertical direction up to the value d.sub.o according to the position of the surface 15 to be sputter coated. The strength of the field components of the magnetron magnetic field Bm parallel to the substrate plane 19 and to the target plane 9, diminishes towards d.sub.o, whereas the respective strength of components of the further magnetic field Ba, Ba′ rises toward d.sub.o. This may be achieved by appropriately selecting, with an eye on FIG. 3, the positions of the second outer pole surfaces 32, especially according to one of the variant (a), (b), (c).

[0201] Thereby, one still achieves that the further magnetic field B.sub.a, B.sub.a′ improves magnetron sputtering but, additionally, provides for unidirectional alignment, parallel to a directional axis, of the magnetic anisotropy along the ferromagnetic material layer which is sputter deposited on surface 15 of the substrate 13.

[0202] Please note that, also with an eye on FIG. 3, the embodiment or variant of positioning the second outer pole surfaces 32 according (a), achieves, on one hand, the desired distribution of field strength, according to FIG. 8 and, on the other hand, allows to provide the dipole arrangement 34 (see FIG. 4) outside the vacuum enclosure 4 with the wall 2.

[0203] As apparent from the discussion of FIGS. 5 and 6, the further magnetic field B.sub.a, B.sub.a′ should be as parallel as possible to the magnetron magnetic field B.sub.m, seen in direction S1. This also prevails if the further magnetic field B.sub.a, B.sub.a′ is exploited as an alignment magnetic field i.e. with the purpose of aligning the direction of magnetic anisotropy in and along a ferromagnetic material layer as sputter-deposited, with respect to a predetermined reference directional—i.e. or orientation-axis over the substrate i.e. over the surface-extent of the layer as being deposited.

[0204] In FIG. 9 there is heuristically shown the effect of the resultant magnetic field B.sub.r on the magnetic anisotropy in the ferromagnetic layer as sputter deposited. In the ferromagnetic material of layer 14, being deposited or as deposited, without applying the alignment field B.sub.r, the magnetic anisotropy is in homogeneous distributed as schematically shown by easy axis e.sub.1 and hard axis h.sub.1.

[0205] Applying the resultant magnetic field B.sub.r according to the invention along an axis r and homogeneously over a predominant area of the sputter-deposited layer material, the magnetic anisotropy in the material of layer 14 is made unidirectional, i.e. the easy axes and, respectively, the hard axes become aligned in a respective unitary direction, e.sub.2d, as shown by e.sub.2 and h.sub.2. Thereby the intersecting angle β of the unidirectionally aligned anisotropy e.g. of the easy axes to the direction r of the applied resultant magnetic field B.sub.r is getting very close to 0°.

[0206] FIG. 10. shows in a representation in analogy to that of FIG. 7 a further embodiment and variant of the invention. According to this variant and embodiment, the first outer pole face 20 has a first leg 21.sub.a on one side of the maximum diameter D.sub.max and a second leg 21.sub.b on the other side of the maximum diameter D.sub.max. Both legs 21.sub.a and 21.sub.b extend along respective linear loci L.sub.a and L.sub.b. The legs per se need not necessarily be linear i.e. straight, but may be curved forth and back or be bent with respect to the respective linear loci L.sub.a, L.sub.b. The maximum diameter extends along the liner locus L.sub.D.

[0207] L.sub.a intersects L.sub.D at an angle α.sub.a, L.sub.b intersects L.sub.D at an angle α.sub.b which is in FIG. 10, about 0°.

[0208] Different further shapes are possible: [0209] (1) α.sub.a=α.sub.b the two legs 21.sub.a and 21.sub.b extend along parallel loci L.sub.a, L.sub.b; [0210] (2) α.sub.a=α.sub.b=0°: If the legs per se are additionally linear and mirrored at D.sub.max, there results a shape of the loop of the first outer pole surface 20 as shown in FIG. 11.

[0211] In the embodiment of FIG. 11 the magnetron magnetic field B.sub.m appears perpendicular to the diameter D.sub.max along a predominant length extent of D.sub.max, seen in direction S1.

[0212] According to FIG. 10 the two parts 32.sub.a and 32.sub.b of the second outer pole surface 32 extend along respective linear loci L.sub.c and L.sub.d. These parts per se need not necessarily be linear, but may be curved forth and back or be bent with respect to the respective linear loci L.sub.c, L.sub.d.

[0213] L.sub.c intersects L.sub.D at an angle α.sub.c, L.sub.d intersects L.sub.D at an angle α.sub.d.

[0214] Different further forms are possible: [0215] (3) α.sub.c=α.sub.d, the two parts 32.sub.a and 32.sub.b extend along parallel loci L.sub.a, L.sub.b; [0216] (4) α.sub.c=α.sub.d=0°: If the parts 32.sub.a and 32.sub.b per se are additionally linear and mirrored at D.sub.max and, further additionally, all conditions addressed above under (2) prevail, there results a shape of the loop of the first outer pole surface 20 as well as a shape and positioning of the parts 32.sub.a and 32.sub.b of the second outer pole surface 32 as shown in FIG. 11. [0217] In this variant and embodiment of the invention, and especially with a course of magnetic field strength as schematically shown in FIG. 8 there results: [0218] a) the magnetron effect is significantly improved by the further magnetic field B.sub.a, ; [0219] b) the further magnetic field B.sub.a, may be or is exploited as an alignment field as was addressed above.

[0220] In FIG. 11 the area 15m of the substrate 13 which is sputter-coated with a ferromagnetic material and along which the directions of magnetic anisotropy become aligned unidirectionally is shown in dash line.

[0221] Further please note, that, as shown in FIG. 11, the first and second inner pole surfaces 22, 30, 30′, may, generically, be mutually overlapping unitary surfaces or might be realized by a single common pole surface.

[0222] As we have discussed in context e.g. with FIG. 3, providing the second outer pole surfaces 32 according to (a) and the second inner pole surfaces as shown at 30, opens the possibility to flexibly position the dipole arrangement 34 for generating the further magnetic field B.sub.a remote from the magnetron which comprises the target 1 and the dipole arrangement generating the magnetron magnetic field B.sub.m. The dipole arrangement 34 may be located on one side of the substrate 13 to be sputter coated, the magnetron on the other side. Especially the dipole arrangement 34 may be positioned outside the reaction space I wherein the substrate 13 is sputter coated.

[0223] This leads to a variant and embodiment according to the invention as schematically shown in a simplified manner in FIG. 12.

[0224] The vacuum enclosure 40 has two opposite walls 42 and 43 which limit the reaction space I.

[0225] As schematically shown by vacuum pump 46, the reaction space I is operated on sputtering atmosphere conditions. The substrate 13 is, in sputtering operation, held on the substrate holder 17. The magnetron 48, including the target 1 and the magnetron dipole arrangement (not shown) for generating the magnetron magnetic field B.sub.m along the sputter surface of the target 1 is mounted along the wall 42.

[0226] The magnetic dipole arrangement 34 is mounted behind or along the inner surface 43, which forms the interface between the vacuum processing atmosphere in the reaction space I and non-vacuum processing atmosphere, especially ambient atmosphere U. Reference number 32 addresses again the second outer pole surfaces, reference number 30 the second inner pole surfaces according to FIG. 3. This arrangement is especially suited if the one substrate 13 or more than one substrates 13 with the respective substrate holder 17 is/are drivingly movable as shown with the double arrow M along the reaction space I and across the target 1, be it in a linear movement or in a circular movement as will be addressed later.

[0227] FIG. 13 shows, again schematically and simplified the mutual positioning and the shapes of the pole surfaces realized at the embodiment or variant of the invention as shown in FIG. 12. In view of the explanations given to FIG. 11 the positioning and the shapes of the pole surfaces in FIG. 13 need no further explanations.

[0228] It may be noted that the movement M of the one or more than one substrates 13 is parallel to the further magnetic field B.sub.a as well as to the magnetron magnetic field B.sub.m, seen in the direction S1 which accords with the z-coordinate direction, so that this arrangement is perfectly suited to establish in a ferromagnetic material layer, sputter deposited on the substrate or substrates 13, the unidirectional magnetic anisotropy as was addressed over the entire surface of the one or more than one substrates 13.

[0229] FIG. 14 shows most schematically substrates 13 according to a variant of the methods or according to an embodiment of the apparatus of the invention, which are drivingly rotatable around a rotational axis A.sub.r. Thereby the normals n on the substrate planes of respective substrate holders (not shown) intersect the axis A.sub.r at an angle φ which is between 45° and 0°, both limits included. If the angle φ is 0° then the normals n are parallel to the axis A.sub.r, the rotational axis A.sub.r is perpendicular to the respective substrate planes, which are arranged along a plane-locus LP.

[0230] FIG. 15 shows most schematically substrates 13 according to a variant of the methods or according to an embodiment of the apparatus of the invention, which are drivingly rotatable around a rotational axis A.sub.r. Thereby the normals n on the substrate planes of respective substrate holders (not shown) intersect the axis A.sub.r at an angle y which is between 45° and 90°, both limits included. If the angle φ is 90° then the normals n are perpendicular to the axis A.sub.r, the rotational axis A.sub.r is parallel to the respective substrate planes, which are arranged along a cylinder locus LC.

[0231] In the variant or embodiment of FIG. 14 the rotational axis A.sub.r may especially be perpendicular to the target plane for target 1 whereas in the variant or embodiment of FIG. 15 the rotational axis may especially be parallel to the target planes of targets 1.

[0232] FIG. 16 shows schematically and simplified a vacuum treatment apparatus 45 according to the invention and performing a sputtering method or substrate manufacturing method according to the invention. Principally it is constructed according to the variant or embodiment of FIG. 15 with φ=0° and the axis A.sub.r parallel to the respective target planes.

[0233] The vacuum treatment apparatus 45 comprises at least one sputtering and alignment apparatus also called alignment station 50 according to the invention and according to the variant or embodiment of the FIGS. 11 to 13, possibly also according to the variant or embodiment of FIG. 10. The vacuum treatment apparatus 45 comprises an outer stationary cylinder 52 with an axis A.sub.C and with an inner cylinder-surface 52, and, coaxially to axis A.sub.C, an inner stationary cylinder 54 with an outer surface 54.sub.o. The inner surface 52, and the outer surface 54.sub.o commonly define a cylindric reaction space I pumped by a pumping arrangement 56.

[0234] Within the cylindric reaction space I a substrate holder carrousel 57 is rotatable—ω—around axis A.sub.C, controllably driven by a drive 58. The substrate holder carrousel 57 holds a multitude of substrates 13 to be vacuum treated. With an eye on the sputter and alignment stations 50, the magnetron 48 is e.g. mounted to the outer cylinder 52, whereas the dipole arrangement 34 for generating the alignment magnetic field B.sub.a is mounted to the inner cylinder 54, outside the reaction space I. Every area of the substrates 13 passes the sputter and alignment station 50 with a movement direction which is parallel to B.sub.a and B.sub.m seen in z direction, which accords with the S1-direction.

[0235] Thus, the directions of magnetic anisotropy in ferromagnetic layers deposited on the substrates 13 are aligned with respect to one reference directional axis r (see FIG. 9). The substrates may be of any shape, e.g. circular disk shaped, rectangular or square.

[0236] Multiple thin layers of ferromagnetic material may be deposited on the substrates by subsequently passing the substrates 13 through respective sputter and alignment stations 50, possibly depositing intermediate non-ferromagnetic layers, e.g. by sputter-stations 51.

[0237] Please note that in the apparatus according to FIG. 16 the targets of the sputter and alignment stations 50 are of a ferromagnetic material. Nevertheless, it is also possible to provide one or the other or all sputter and alignment stations 50 with non-ferromagnetic targets and exploit the inventively applied further magnetic fields merely for improving the magnetron effect. Then these stations 50 become rather improved sputtering stations than sputtering and alignment stations.

[0238] Further, in the embodiment of FIG. 16 the magnetrons 48 could be mounted to the inner cylinder 54 and the dipole arrangement 34 to or along the outer cylinder 52. This especially if the inner cylinder 54 is hollow and allows easy handling of the magnetrons 48 e.g. for the exchange of the targets 1.

[0239] As apparent, the vacuum treatment apparatus 45 may comprise one or more than one sputter and alignments stations 50 according to the invention, one or more than one improved sputtering stations 50 according to the invention and possibly one or more than one further vacuum treatment stations 51 as of etching stations, sputtering stations, etc.

[0240] In the embodiment or variant of FIG. 16 the substrates are rotated around axis A.sub.C with the normals N.sub.o on their extended surfaces pointing in radial direction with respect to axis A.sub.c.

[0241] FIGS. 16 and 17 show schematically and simplified a further vacuum treatment apparatus 55 according to the invention and performing a sputtering method or substrate manufacturing method according to the invention. This variant or embodiment generically accords with the variant or embodiment of FIG. 14 with the rotational axis A.sub.r perpendicular to the target planes.

[0242] In this embodiment or variant substrates 13 are deposited on a disk or ring-shaped substrate carrousel 67 for multiple substrates 13. The disk or ring-shaped substrate carrousel 67 is rotatable around an axis A.sub.D, controllably driven by a drive 68. The vacuum enclosure 60 defines a disk or ring-shaped reaction space I wherein the disk or ring-shaped substrate carousel 67 is rotatable. Besides of a cylindric wall 69, coaxial to axis A.sub.D, the vacuum enclosure 60 comprises a top wall 70 with an inner surface 70.sub.i, and a bottom wall 72 with an inner surface 72.sub.i, extending perpendicularly to the axis A.sub.D. Substrates 13 are arranged along the periphery of the substrate holder carousel 67 with their normals N.sub.o on their extended surfaces parallel to the axis A.sub.D.

[0243] In the sputtering and alignment station 50, the magnetic dipole arrangement 34 is mounted outside the reaction space I, along or outside the bottom wall 72, whereas the magnetron 48 is mounted to the top wall 70. The sputter and alignment station 50 according the invention is mounted in alignment with the moving path of the substrates 13 as rotated around axis A.sub.D.

[0244] In analogy to the variant and embodiment according to FIG. 16, also in the variant and embodiment of FIG. 17 multiple sputter and alignment stations 50 may be provided so as to deposit on the substrates 13 multiple thin ferro-magnetic layers possibly with interposed layers of non-ferromagnetic material as sputter-deposited by sputter-stations 51.

[0245] If the stations 50 are not exploited for aligning the magnetic field along a directional axis in a respectively deposited layer of ferromagnetic material but are exploited merely as improved magnetron sputtering stations, then the substrates 13 may be drivingly rotated—ω.sub.13—around their central axes A.sub.13, which also prevails for such case at the embodiment of FIG. 16.

[0246] With an eye on exploiting the sputtering station as a alignment station one should consider: If a substrate 13 is moved pass such a station 50 for aligning the magnetic anisotropy in the ferro-magnetic layer as deposited along an axis r (see FIG. 9) then the substrate should pass the station 50 maintaining a constant directional orientation with respect to the direction of the resulting magnetic field B.sub.r of the station 50. This is exemplified in FIG. 18.

[0247] The stationary station 50 generates, seen in direction S1, a homogeneous resulting magnetic field B.sub.r in one direction, according to a linear locus L.sub.50. A substrate 13 is moved—M.sub.13—relative to the station 50 whereby the complete extended surface of the substrate passes through the area of field B.sub.r. V.sub.13 indicates the orientation of the substrate 13 in the x/y plane. At least during a time span, in which the substrate 13 becomes exposed to the magnetic field B.sub.r of the station 50, the angle γ between the orientation V.sub.13 of the substrate 13 and the locus L.sub.50 should be kept constant.

[0248] In the variant and embodiment according to FIG. 16 this is realized.

[0249] In the variant and embodiment according to FIG. 17 the movement of the substrates 13 passing in a rotational movement around axis A.sub.D the one or more than one stations 50 acting as sputter and alignment stations is additionally to be controlled to fulfil the condition as described in

[0250] context with FIG. 18.

[0251] FIG. 19 shows schematically and simplified one possibility of fulfilling the condition as exemplified in FIG. 18 at a variant and embodiment of FIG. 17.

[0252] The station 50 acting as a sputter and alignment station is rigidly mounted with respect to the vacuum recipient 60, as schematically shown. With respect to a selected angle reference R, the angle β.sub.o of the orientation direction of the resulting magnetic field B.sub.r is known.

[0253] The substrate 13, shown as rectangular, but which may be of any desired shape, is held on a substrate holder 66 which is rotatable around the axis A.sub.13 on the substrate holder carousel 67 A reference orientation direction on the substrate is established and thus known. Such reference orientation may be marked on the substrate 13 as by a flat, but needs not to be physically recognizable on the substrate 13. By means of an angle sensor 74 coupled to the rotation axis A.sub.13 of the substrate holder 66 the prevailing angle between the prevailing orientation direction V.sub.13 of the substrate and the direction V.sub.50 of the magnetic field B.sub.r is measured. By means of a negative feedback control loop the angle is controlled to be constant on a selected angle value γ.sub.o. The prevailing measured angle is compared at a difference forming unit 76 with the desired angle γ.sub.o and the resulting difference Δ, the control difference, is led via an appropriate controller (not shown) to the control input of a rotation drive 80 for the substrate holder 66 around axis A.sub.13, as the adjusting member in the negative feedback control loop. Thereby the substrate 13 passes the station 50 at a constant, selectable angle γ.sub.o with respect to the direction of the magnetic field B.sub.r.