Sputtering Targets

Abstract

The present invention relates to a sputtering target (10), a coating system (30) and a coating method. The sputtering target (10) comprises a base plate (12) and a target plate (14) fixed thereon and made of a first sputtering material, the target plate having a surface (16) and a number of recesses (18). A number of inserts (20) are arranged in the recesses (18). At least some of the inserts (20) are made of a second sputtering material, the second sputtering material having a higher sputtering rate than the first sputtering material. The object of the present invention is to achieve a particularly uniform coating. This is achieved by the fact that the inserts (20) made of the second sputtering material have a size (D 1 ) of the inserts measured in a measuring direction parallel to the surface (14). 1 ,D 2 ) is formed so as to increase in the depth direction (T) from the surface (14) to the base plate (12).

Description

[Technical field]

[0001] The present invention relates to a sputtering target, a coating system and a coating method. [Background technology]

[0002] Sputtering targets are used in sputtering techniques, in particular for coating substrates. In this process, the sputtering target is sputtered by particle bombardment. The components of the sputtered target enter the gas phase and can be used, for example, as materials for surface coatings.

[0003] In the case of a PVD coating method using cathodic sputtering, a sputtering target is connected as a cathode in a coating chamber of a coating system and is sputtered by positively charged particles, in particular gas and / or metal ions.

[0004] In addition to sputtering targets made of only one material, sputtering targets made of several materials, in particular different metals, are known. In this connection, in particular, designs are known in which the sputtering target comprises a plate made of a first material, in which holes are provided, into which plugs of another material are inserted.

[0005] For example, US 6,852,201 discloses a sputtering component for carrying out a PVD coating method in which a layer containing a plurality of metal elements is provided on a substrate by sputtering caused by the bombardment of gas ions. The sputtering component consists of a titanium base plate and includes a hole into which an aluminum plug is pressed. Since the sputtering rate of aluminum is greater than that of titanium, the aluminum plug has a concave curved surface on the surface exposed to the base plate.

[0006] DE 2940369 A1 discloses a target for sputtering at least two different metallic materials. A plate made of the material to be sputtered is provided with a continuous hole with a circular cross section, into which a bolt made of the second material to be sputtered is inserted with a tight fit. The bolt is provided with a thickened end which engages in an enlarged end area of ​​the hole designed as a counterbore. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US6,852,201 [Patent Document 2] DE2940369A1 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the invention is to propose a sputtering target, in particular for use in cathode sputtering, which allows a particularly uniform coating. [Means for solving the problem]

[0009] This object is achieved by a sputtering target according to claim 1, a coating system according to claim 14 and a coating method according to claim 15. The dependent claims refer to advantageous embodiments of the invention.

[0010] A sputtering target according to the present invention comprises a base plate and a target plate secured thereon, the target plate comprising a plurality of inserts disposed in recesses formed in a surface of the target plate.

[0011] The base plate and / or the target plate are preferably flat and / or rectangular. The base plate and the target plate are preferably at least substantially the same size. The insert is preferably shaped to properly fill the recess, where applicable, with a concavely curved recess in the surface. The recess and the insert that fits therein can be of any desired cross-sectional shape, e.g., circular, triangular, rectangular, square, polygonal, elliptical, etc. Examples of inserts of various cross-sectional shapes are described below.

[0012] The target plate consists of a first sputtering material and at least some of the inserts, more preferably the majority of the inserts and particularly preferably all the inserts, consist of a second sputtering material. Sputtering material is understood to mean a solid material that can be used in a sputtering process, in particular a coating process. Metals, in particular pure metals, are preferred, but other materials such as carbon can also be used. Examples of sputtering materials are given below:

[0013] The material of the target plate is different from the material of the plug. The second sputtering material constituting the plug has a higher sputtering rate than the first sputtering material constituting the target plate. For example, the second sputtering material may have a sputtering rate at least 20%, preferably at least 50% or even 100% higher than the first sputtering material. As known to those skilled in the art, the sputtering rate is a material-dependent parameter that specifies the average number of target atoms released per incident ion during the sputtering process. As a result, for areas where ions are uniformly bombarded, the sputter erosion rate is higher on the insert made of the second sputtering material compared to the target plate.

[0014] According to the invention, at least some of the inserts made of the second sputtering material, preferably the majority of the inserts, and particularly preferably all of the inserts, have a shape in which the size (extension) measured in a measurement direction parallel to the surface increases continuously in the depth direction from the surface to the base plate. This should at least be understood to mean that for a given insert, at a first shallower depth it has a first size (extension) in the measurement direction and at a second deeper depth it has a second size (extension) in the measurement direction, the second size always being greater than the first size. The size dimension therefore increases strictly monotonically with depth. Preferably, the respective cross-sectional area of ​​the insert also increases correspondingly in the depth direction.

[0015] In the following, the terms "pyramid" or "pyramidity" are sometimes used to refer to the enlarged shape of the insert, but may refer to a cone or wedge shape, i.e., a circular cross-sectional shape and / or a continuous linear profile, the latter being preferred, but not limited thereto.

[0016] The conical shape of the insert has in each case proven to be advantageous for achieving a composition of the sputtered material that is as uniform as possible over the entire service life of the sputtering target. When used in a coating system, the coating produced is composed of the components of the sputtered material. The inventors have determined that in the case of conventional sputtering targets with cylindrical inserts that have become worn to an advanced degree, the proportion of the second sputtering material forming the insert relative to the first sputtering material forming the target plate decreases.

[0017] The sputtering target of the present invention counteracts this tendency and preferably at least partially, or in the ideal case at least substantially completely compensates for the change in the relative proportion of the second sputtering material, so that when used in a coating system, a more uniform layer composition can be achieved throughout the service life of the sputtering target.

[0018] The shape of the insert, which increases in size in the depth direction, can be realized in various designs. For example, the insert may have one or more steps in the longitudinal section, in which the size of the insert increases abruptly in the measuring direction. According to the invention, the shape has a continuous, i.e. stable, increase in size in the depth direction, which is preferably linear, for example at least partially resulting in the shape of a truncated cone in the case of a circular cross section, or in the case of a rectangular or square cross section, in the shape of a truncated pyramid. However, it is also conceivable that the size in the depth direction progresses nonlinearly. Particularly preferably, the insert is formed in a continuous conical or pyramidal shape.

[0019] It is possible that all inserts made of the second sputtering material have the same shape and dimensions. However, it is also possible that the shapes of the different inserts, in particular the degree of conicity and the dimensions, differ from each other. Corresponding embodiments are described below.

[0020] In the preferred case where the outer contour extends in a straight line, the outer contour may extend obliquely, i.e. at least at a part of each insert, as compared to a square or cylindrical shape when viewed in longitudinal section of the insert. The cone angle may, for example, be in the range of 1 to 20°. Here, the depth direction is perpendicular to the surface, so that the angle formed between the edge and the surface is, for example, 70° to 89°. As the cone angle, a cone angle of 4° to 15° (corresponding to an angle between the edge and the surface of 75° to 86°) is preferred, a cone angle of 6° to 12° (angle between the edge and the surface of 78° to 84°) is particularly preferred. As will be explained below, the cone angles of the inserts of different targets may be different.

[0021] The preferred increase in the cross-sectional area of ​​the insert may vary in different embodiments. Preferably, the cross-sectional area increases by 4-40%, particularly preferably by 15-30%, over a distance of 5 mm in the depth direction. In the case of inserts with a circular cross-sectional area, slightly lower values ​​of 8-30%, particularly preferably 15-25%, may be preferred.

[0022] The above-mentioned specification of the degree of conicity has proven to be advantageous in particular for material combinations in which the second sputtering material has a sputtering rate 50% to 150% higher than the first sputtering material.

[0023] The base plate and the target plate are preferably placed one directly on top of the other in a plan view. According to a preferred embodiment, the base plate can be provided with a recess, preferably formed in the surface of the base plate facing the target plate, but not completely penetrating the base plate. Some, more than a few, or preferably all of the inserts made of the second sputtering material preferably protrude into the recess of the base plate and can therefore more preferably be substantially completely filled therewith. As a result, the material of the target plate can be utilized in an improved manner, since the sputtering target can be used for a longer time without the material of the base plate being significantly sputtered.

[0024] The base plate serves on the one hand to mechanically hold and fix the sputtering target and preferably on the other hand to ensure good heat distribution and dissipation. Preferably, the base plate consists entirely or at least predominantly of at least substantially pure copper or a copper alloy. The base plate can be provided with fastening elements or engagement structures for fastening elements, e.g. holes for engagement with fastening elements.

[0025] The first and second sputtering materials may in particular be selected from the group comprising C, B, Al, Si and elements of groups 4 to 6 of the periodic table according to IUPAC (1988), either in pure form or as compounds, alloys or sintered materials thereof. In a particularly preferred embodiment, the material combination of the first and second sputtering materials may be, for example, titanium / aluminum.

[0026] The target plate and / or base plate preferably have a rectangular shape, in particular elongated, i.e. a length that is more than three times, preferably more than five times, its width. Its width may be, for example, in the range of 50 to 200 mm, preferably 70 to 150 mm. Its length may be, for example, in the range of 200 to 1000 mm, preferably 300 to 700 mm. The thickness of the target plate is preferably relatively thin compared to its length and width, for example in the range of 3 to 30 mm, in particular 5 to 15 mm.

[0027] The inserts may be arranged in an annular region on the target plate, i.e. along a closed strip encircling the center of the target plate. "Annular" need not necessarily be understood to mean circular. Indeed, for the preferred rectangular shape of the target plate, the preferred arrangement of the inserts follows an elliptical path, or rather a rounded rectangle.

[0028] The inserts are preferably arranged along a line on the target plate, with successive inserts being in each case offset towards the side of the line, this arrangement having proven advantageous for allowing (accommodating) a relatively large number of inserts along the main area subjected to load during cathode sputtering.

[0029] It is possible to use inserts of different shapes and / or sizes and to arrange them at different positions on the target plate. This can be particularly advantageous if different sputtering conditions are generated depending on the position on the target plate, for example due to differences in the magnetic field strength when the sputtering target is arranged on the magnetron cathode. In this way, any non-uniformities can be compensated. For example, inserts of different cross-sections, in particular different diameters and / or inserts with a more or less pronounced conicity can be used. For example, in the case of a rectangular target plate, inserts of a first type with a first size and conicity can be arranged along the long side of the target plate and the second type arranged on the short side. In this way, the effects of different position-dependent sputter erosion, resulting from possible non-uniform bombardment of ions, can be compensated in such a way that the composition of the eroded material is as uniform as possible along the length of the sputtering target. Such a non-uniform distribution of erosion can be reacted to, for example, by inserts arranged in a first particularly heavily loaded area of ​​the target, which has no or a lower conicity than a second less loaded area of ​​the target.

[0030] It has been shown that when using rectangular targets on unbalanced magnetron cathodes, different areas of the target are subjected to different amounts of loading depending on the type of electrical excitation. Operation with direct current (DC) voltage results in greater sputter erosion on the short sides, whereas operation with HIPIMS (High Power Impulse Magnetron Sputtering) results in greater erosion in the longitudinal center. Thus, for use with HIPIMS, it is possible to provide targets that are not pyramidal or have a lower pyramidal profile, for example in areas with lengths of 100-350 mm, preferably 200-300 mm, with the inserts being more centrally located along the longitudinal sides than along the short sides.

[0031] Inserts with a circular cross section are known, tried and tested, but it has been shown that in the case of significant conicity, i.e. increasing diameter along the depth direction, it may be difficult to arrange the inserts closely enough to obtain a high surface proportion of the second sputtering material. Therefore, according to a preferred embodiment, in particular inserts with a strip-shaped cross section can be used. This should be understood to mean a cross-sectional shape whose maximum longitudinal dimension, i.e. length, is significantly greater than its transverse dimension, i.e. width, relative to the length. The length of the strip-shaped insert preferably corresponds to at least twice its width, preferably at least three times its width. Even longer designs, with a length / width ratio of at least 4, 5, 8 or 10, have also proven to be favorable. Preferably, the shape of the strip is at least substantially rectangular, i.e. has two at least substantially parallel long edges. The ends are preferably rounded. The use of strip-shaped inserts makes it easier to provide a relatively large portion of the surface of the sputtering target with the second sputtering material.

[0032] The strip-shaped inserts may have a width at the upper side of, for example, 5-20 mm, preferably 8-16 mm, particularly preferably 10-15 mm. Their length depends on the arrangement in the rectangular target plate, in the case of a transverse or oblique arrangement short inserts may be used, in the case of a longitudinal arrangement long inserts may be used. In the short variants, the length may be, for example, 20-100 mm, preferably 25-80 mm, particularly preferably 30-50 mm. In the long variants, the length may be, for example, up to 500 mm.

[0033] The strip-shaped insert may have a conicity in which its length and / or width increases in the depth direction, preferably both the width and the length.

[0034] The strip-shaped inserts can be arranged preferably parallel to one another. An oblique, i.e. diagonal, arrangement of the inserts on the rectangular target surface has proven to be particularly advantageous, the inserts being arranged with their longitudinal axis at an angle of preferably 20-70°, particularly preferably 30-60°, in particular 45°+ / -10° to the longitudinal and / or lateral edges of the rectangular target surface. In this way, a good uniformity of distribution of the first and second sputtering materials on the surface of the sputtering target can be achieved.

[0035] The invention further relates to a coating system, in which a coating chamber can be evacuated in a known manner by suitable means and in which a substrate to be coated can be placed. At least one cathode, preferably several cathodes, in particular magnetron cathodes, are arranged in the coating chamber. A sputtering target according to any one of the claims is attached to at least one cathode, preferably several cathodes or to all cathodes.

[0036] Finally, the invention relates to a coating method, in which a sputtering target according to the invention is sputtered in vacuum by cathodic sputtering and a coating of the sputtered components of the sputtering target is applied to a substrate.

[0037] In the following, embodiments of the invention are explained in more detail with reference to the drawings. [Brief description of the drawings]

[0038] [Figure 1] FIG. 2 is a perspective view of a first embodiment of a sputtering target with an insert partially inserted. [Diagram 2] FIG. 2 is a plan view of the sputtering target shown in FIG. [Diagram 3] FIG. 3 is a longitudinal cross-sectional view of the target taken along line AA in FIG. 2. [Figure 4]FIG. 4 is an enlarged view of region B in FIG. 3, showing the shape of an insert according to a first embodiment of the sputtering target. [Diagram 5] FIG. 1 shows a schematic diagram of a coating system. [Figure 6] FIG. 4 is a plan view showing a second embodiment of a sputtering target with an insert inserted therein. [Figure 7a] FIG. 7 shows an insert of the sputtering target in FIG. 6. [Figure 7b] FIG. 7 shows an insert of the sputtering target in FIG. 6. [Figure 7c] FIG. 7 shows an insert of the sputtering target in FIG. 6. [Figure 8] FIG. 11 is a plan view showing a third embodiment of a sputtering target with an insert inserted therein. [Figure 9] 1 is a graph showing the progress of the proportion of sputtering material with respect to erosion of a sputtering target. [Figure 10] FIG. 13 is a plan view showing a fourth embodiment of a sputtering target with an insert inserted therein. [Figure 11] FIG. 13 is a plan view showing a fifth embodiment of a sputtering target with an insert inserted therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] It should be understood that the drawings are illustrative and are not necessarily to scale.

[0040] FIG. 1 illustrates a first embodiment of a sputtering target 10 .

[0041] The sputtering target 10 has a flat rectangular shape and comprises a rectangular base plate 12 made of copper and a target plate 14 made of a first sputtering material, in this case for example pure titanium, disposed thereon.

[0042] The front surface 16 of the target plate is provided with a recess 18 into which an insert 20 made of a second sputtering material, in this case pure aluminum by way of example, is inserted. The insert 20 is also called a plug.

[0043] 1, to facilitate understanding, the right half of the sputtering target 10 is shown without an insert 20 inserted therein, while the left half shows the recesses 18 with an insert 20 inserted therein. In practice, an insert 20 is inserted into each of the recesses 18 of the sputtering target 10 such that the recesses 18 are completely or at least largely filled. The upper side of the insert 20 in each case forms a continuous plane with the surface 16 of the target plate 14 or is adjacent to the surface 16 but has a concave upper recess (not shown).

[0044] Sputtering target 10 is shown in plan view in Figure 2. The recesses 18 and the inserts 20 inserted therein are disposed on surface 16 in an annular array along a peripheral strip that is in the shape of a narrow, elongated rectangle with significantly rounded corners. Along at least the long edges of sputtering target 10, successive inserts 20 are laterally offset in alternating directions relative to one another and are disposed in close succession such that their edges nearly touch.

[0045] At the corners, the target plate 14 has recesses and the underlying base plate 12 has screw holes for fastening the sputtering target 10 to a cathode of a coating system, as described below in connection with Figure 5. In addition, the target plate 14 and base plate 12 have a row of centrally located holes that are also used for mounting purposes.

[0046] Fig. 3 shows the arrangement and shape of the base plate 12, the target plate 14, and the recess 18, as well as the insert 20, in a longitudinal cross section of the sputtering target 10 taken along the line AA in Fig. 2. Fig. 4 shows an enlarged view of region B in Fig. 3.

[0047] In the illustrated example, the inserts 20 each have the same shape. Each insert 20 has the shape of a truncated cone with a smaller upper diameter D1 at the surface 16 and a larger lower diameter D2. Thus, in a depth direction T extending perpendicularly from the surface 16 towards the base plate 12, the lateral dimension, measured here as a diameter, increases linearly from diameter D1 to diameter D2 in a measurement direction parallel to the surface 16. As a result, the cross-sectional area of ​​the insert 20, measured in each case parallel to the surface 16, increases accordingly.

[0048] In the enlarged longitudinal section of Figure 4, it can be seen that, with respect to the contour of the insert 20 shown, the side edges of the insert 20 adjacent to the edges of the recess 18 extend obliquely, i.e. at a conicity angle α with respect to the vertical and at an angle β with respect to the surface 16 (where, obviously, β = 90° - α is legal).

[0049] In the preferred exemplary embodiment shown, the angle α is about 8° and therefore the angle β is about 82°.

[0050] 4 also shows that the insert 20 extends deeper into the recess 22 of the base plate 12 than corresponds to the thickness T1 of the target plate 14. Here, the base plate 12 has a thickness T2, and the insert 20 extends into the base plate 12 an amount T3.

[0051] In a preferred embodiment, the length or more precisely the depth (T1+T3) of the insert 20 is about 4-20 mm, preferably about 7 mm. The upper diameter D1 of the insert 20 is for example in the range of 10-20 mm, preferably about 15 mm, and the lower diameter D2 is for example 5-20% larger than D1, preferably about 13% larger.

[0052] 5 shows diagrammatically a coating system 30 with a vacuum chamber 32 in which, by way of example, four cathodes 40, designed as unbalanced magnetrons, are arranged around a substrate table 38. Each cathode 40 is equipped with one sputtering target 10 in each case.

[0053] Connected to the vacuum chamber 32 are means 34 for creating a vacuum (a pumping system) and means 36 for supplying process gases and, where applicable, reactive gases.

[0054] The cathode 20 , substrate table 38 , and anode 44 , which are disposed within the vacuum chamber 32 , are connected to a power supply system 42 .

[0055] Coating system 30 can be constructed and operated, for example, as disclosed in applicant's International Publication No. WO 98 / 46807, the contents of which are incorporated herein by reference, particularly with respect to the electrical configuration of the elements of coating system 30 shown and with respect to the process during coating.

[0056] Within the vacuum chamber 32, a plasma is generated between the cathode 40 and the anode 44 using a voltage by a power supply system 42 to sputter the sputtering target 10. Thus, a substrate placed on a substrate table 38 becomes coated with the sputtered components of the sputtering target 10.

[0057] During operation of the coating system 10, material is eroded from the surface 16 of the sputtering target 10 primarily along erosion channels that extend annularly on the sputtering target along the array of inserts 20 (see FIG. 2). Material is eroded from both the associated exposed surfaces of the target plate 14 and from the inserts 20.

[0058] However, the erosion is not uniform but varies between the first sputtering material, in this case titanium, and the second sputtering material, in this case aluminum, depending on the sputtering rates of each of the aforementioned materials.

[0059] Below, sputtering rate values ​​for some materials at 600 eV are given as examples (for sputtering with Ar ions). Al (aluminum) 1.24 Ti (Titanium) 0.58 Cr(Chromium) 1.3 Si (silicon) 0.53 V(vanadium) 0.7 Ta (Tantalum) 0.62

[0060] Thus, for the preferred material combination of titanium / aluminum, the sputtering rate of the second sputtering material is approximately 100 percent higher than the sputtering rate of the first sputtering material, titanium.

[0061] After a certain operating time, due to the high sputtering rate of the second sputtering material constituting the insert 20, the surface 16 of the sputtering material is no longer flat, but rather the insert 20 becomes deeper like recesses. These recesses provide a partial shielding against impinging ions, and the respective proportions of the first and second sputtering materials, taking into account the above-mentioned sputtering rates, do not result directly from the cross section of the insert 20 and the surface of the target plate 14, but rather the situation is more complicated. In any case, however, a comparative example of a cylindrical insert 20 not according to the invention shows that the proportion of the second sputtering material in the vacuum chamber 32, or rather the coating produced on the substrate, decreases throughout the service life of the sputtering target 10.

[0062] In the case of the conical shape of the insert 20 shown in Figures 3 and 4, the insert increases in size in the depth direction, gradually exposing larger areas due to progressive erosion, which offsets and ideally completely compensates for the decrease in the proportion of the second sputtered material.

[0063] In the above-described embodiment of the sputtering target 10, all inserts 20 have the same shape, however, the shapes of individual inserts 20 of the same sputtering target 10 may differ from one another, in particular the inserts 20 may have different conicities (i.e., in particular different angles of conicity), or the inserts 20 may have a cylindrical shape, i.e. a shape that has no conicity.

[0064] Therefore, as an alternative embodiment (not shown), a sputtering target 10 is proposed having the same shape as the target plate 14 and the same number and arrangement of inserts 20 as the illustrated sputtering target 10, where the cylindrical, i.e. non-pyramidal, inserts 20 are provided centrally along the length (long side) of the target plate 14, for example along a distance of 250 mm. This type of target is particularly suitable for operation according to the HIPIMS method, where more erosion occurs in the longitudinal center.

[0065] Figures 6 and 7a-7c show a sputtering target 110 and its insert 120 according to a second preferred embodiment. The sputtering target 110 according to the second embodiment corresponds to the sputtering target 10 according to the first embodiment to a large extent, and identical parts are given the same reference numerals. Like the sputtering target 10, the sputtering target 110 comprises a rectangular target plate 14 having a base plate 12 (not visible in Figure 6) disposed thereunder.

[0066] In the following, only the differences between both embodiments will be mentioned.

[0067] The second embodiment differs from the first embodiment in that the recesses 118 have a different cross-sectional shape and are fitted with different inserts 120. The inserts are each strip-shaped, i.e., elongated rectangular in cross-section, but with rounded ends.

[0068] The recess 118 and the insert 120 are cone-shaped, i.e. they increase in size in the depth direction T. At the surface 16, the insert 120 has a length L1 and at the lower end a length L2 which is greater than L1. Transversely, the width B2 at the lower end is also greater than the width B1 of the surface 16. Due to the elongated shape, the lengths L1, L2 are in each case significantly greater than the associated widths B1, B2, in this case by a factor of about 10. The different insert 122, i.e. the shorter insert, is properly received snugly in the corresponding recess only at the longitudinal ends of the target plate 14.

[0069] In the case of the sputtering target 110 according to the second embodiment, the target plate 14 is preferably made of titanium and the insert 120 is made of aluminum. The width of the insert 120 increases in the depth direction T from a width B1 to a width B2, and the side walls extend at an angle β1 when the insert 120 is viewed longitudinally. At the same time, the length of the insert 120 increases in the depth direction T from a length L1 to a length L2, and the side walls extend at an angle β2 when the insert 120 is viewed transversely. Thus, the cross-sectional area of ​​the insert 120 increases in the depth direction T from the surface 16 (parallel to the surface 14) from an area L1×B1 to an area L2×B2 (wherein the rounded portions are not taken into account in this calculation).

[0070] The dimensions of the sizes L1, L2, B1, B2, β1, β2 may be different in different embodiments. In particular, it is possible for L1=L2 or B1=B2, i.e. the insert 120 may be, for example, only conical in the longitudinal or transverse direction. In particular, it may turn out to be simpler from a manufacturing point of view to provide only transverse conicity rather than longitudinal conicity (i.e. L1=L2), since the effect of the transverse conicity is in any case more pronounced.

[0071] In a preferred exemplary embodiment, the insert 120 may be characterized, for example, by the following values: L1=95mm L2 = 95mm (at a depth T of 5mm) B1=15mm B2 = 18mm (at a depth T of 5mm) β1=73.3° β2=90°

[0072] This results in an increase in cross-sectional area of ​​approximately 20% at a depth of 5 mm compared to the surface 16 .

[0073] According to the embodiment of FIG. 6, the elongated inserts 120 extend parallel to one another on the surface 16 in oblique alignment with the edge of the target plate 14, in this case at an angle of approximately 45°.

[0074] Due to the elongated shape of the insert 120, a higher ratio of the material of the insert 120 (here aluminum) to the material of the target plate 114 (here titanium) can be achieved at the surface 16 compared to the circular cross section of the insert 20 according to the first embodiment. In particular, due to the cone-like shape of the insert 120, a significant increase in the ratio of the material of the insert 120 to the total surface area can be achieved in a simpler way, without causing problems when arranging the inserts 120 next to each other.

[0075] 8 shows a sputtering target 210 according to a third embodiment. The sputtering target 210 according to the second embodiment corresponds substantially to the sputtering target 110 according to the second embodiment, and like parts are again given the same reference symbols. In the following, only the differences between the embodiments will be mentioned.

[0076] In the third embodiment, the recesses 218 and the inserts 220 inserted therein are also elongated, but have a significantly shorter width-to-length ratio of about 1:4. The inserts 220 are aligned at an angle of about 45° to the edge and are arranged in two parallel rows along the longitudinal edge of the target plate 14. The inserts 220 are also pyramidal, i.e., their length and / or width increase in the depth direction T (not shown in FIG. 8).

[0077] The drawings of the insert 120 according to Figures 7a to 7c also apply to the insert 220, i.e. the dimensions L1, L2, B1, B2, β1, β2 apply to its shape and increasing size in the depth direction T. In a preferred exemplary embodiment, these dimensions may be selected as follows: L1=31mm L2 = 34mm (at a depth T of 5mm) B1=15mm B2 = 18mm (at a depth T of 5mm) β1=73.3° β2=73.3°

[0078] This results in an increase in cross-sectional area of ​​approximately 32% at a depth of 5 mm compared to the surface 16 .

[0079] 9 shows the results of coating tests using different sputtering targets 210 according to the third embodiment. The coatings were applied in the system 30 as described above using a sputtering target 210 consisting of a titanium target plate 14 and an aluminum insert 220. The aluminum content in the produced layer (at.% of the metal layer content) is shown against the erosion of the sputtering target 210 (in mm).

[0080] In figure 9 three different curves are shown for different conicities of the insert 220, in each case indicated by the area ratio between the cross-sectional area at the surface 16 and the cross-sectional area at the bottom end. Thus the bottom line indicated by 1:1 shows an insert with no increase in size with depth (comparative example) and the top two lines show curves for low conicity (1:1.2, i.e. a 20% increase in cross-sectional area at a depth of 5 mm) and for a higher conicity (1:1.3, i.e. a 30% increase in cross-sectional area at a depth of 5 mm).

[0081] In the comparative example of the non-pyramidal insert (line 1:1), the Al content drops sharply from an initial 58 at.% to less than 50 at.% when the sputtering target is eroded to a depth of 5 mm. Even a pyramidal shape with a 20% increase in cross-sectional area reduces the drop in Al content significantly to about 54 at.%. An even greater pyramidal shape with a 30% increase in cross-sectional area still results in a drop in Al content, but this time it is less pronounced.

[0082] 10 and 11 show sputtering targets 310, 410 according to fourth and fifth embodiments. The sputtering targets 310, 410 according to the fourth and fifth embodiments correspond substantially to the sputtering targets 110, 210 according to the previous embodiments, and like parts are again given like reference numerals. In the following, only the differences between the respective embodiments will be mentioned.

[0083] In the fourth and fifth embodiments, the recesses 318, 418 and the inserts 320, 420 inserted therein are not arranged diagonally to the edge of the target plate 14, but rather parallel, in the example of Fig. 10 they are parallel to the short side and in the example of Fig. 11 they are parallel to the long side. Again, the inserts 320, 420 are pyramidal, i.e. their length and / or width increase in the depth direction T (not shown in Figs. 10 and 11).

[0084] In summary, the conicity of the inserts of the sputtering target is shown to be used to homogenize the relative proportions of coating materials in the layer being produced. Such conicity can be provided for inserts 20, 120, 220, 320, 420 of different cross-sectional shapes and arrangements in the target plate 14.

Claims

1. A sputtering target (10), comprising: A base plate (12); a target plate (14) made of a first sputtering material secured thereto and having a surface (16) and a plurality of recesses (18) formed thereon; a plurality of inserts (20) disposed within the recess (18), at least some of which are made of a second sputtering material; the second sputtering material has a higher sputtering rate than the first sputtering material; At least a portion of the insert (20) made of the second sputtering material has a size (D １ , D ２ ) is formed so as to continuously increase in the depth direction (T) from the surface (16) to the base plate (12). Sputtering target.

2. At least some of the inserts (20) made of the second sputtering material are shaped to be at least partially conical or pyramidal. The sputtering target according to claim 1 .

3. At least some of the inserts (20) made of the second sputtering material are formed such that their cross-sectional area increases in the depth direction (T) by 4-40% over a depth of 5 mm.

3. The sputtering target according to claim 1 or 2.

4. At least some of the inserts (20) made of the second sputtering material are shaped such that, in longitudinal cross section, their edges extend at an angle of between 70° and 89° relative to the surface (14); 4. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

5. The base plate 12 includes a recess (22); The insert (20) made of the second sputtering material protrudes into the recess (22) of the base plate (12).

5. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

6. the first sputtering material is titanium; the second sputtering material is aluminum; 6. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

7. The base plate (12) consists entirely or at least predominantly of copper or a copper alloy.

7. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

8. The insert (20) is disposed in an annular region on the target plate (14).

8. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

9. The inserts (20) are positioned along a line on the target plate (14); the inserts (20) are in each case arranged to be offset towards the side of the line, 9. The sputtering target according to claim 1, wherein the sputtering target is a metal oxide.

10. The two inserts (20) arranged at different positions on the target plate (14) have different shapes and / or sizes.

10. The sputtering target according to claim 1 ,

11. The insert (120, 220, 320, 420) has a strip-shaped cross section having a length at least twice its width.

11. The sputtering target according to claim 1 .

12. the length and / or the width increasing in the depth direction (T); The sputtering target of claim 11.

13. The target plate (14) is rectangular; the strip-shaped inserts (120, 220) are aligned at an angle of 20 to 70° with respect to the longitudinal and / or lateral edges of the target plate (14); 13. The sputtering target according to claim 11 or 12.

14. A coating chamber (32); a means (34) for creating a vacuum in said coating chamber (32); a means (38) for positioning a substrate to be coated within said coating chamber (32); at least one cathode (40) disposed within the coating chamber (32); A sputtering target (10) according to any one of claims 1 to 13 is mounted on the cathode (40). Coating system.

15. The sputtering target (10) according to any one of claims 1 to 13 is sputtered in a vacuum by cathodic sputtering, and a coating of the sputtered components of the sputtering target (10) is provided on a substrate. A coating method comprising the steps of:

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