Sputtering target

Abstract

This invention relates to a sputtering target (10), a coating system (30), and a coating method thereof. The sputtering target (10) includes a base (12) with a target plate (14) fixed to the base and made of a first sputtering material. The target plate has a surface (16) and a plurality of recesses (18) formed in the surface. A plurality of inserts (20) are arranged in the recesses (18). At least some of the inserts (20) are made of a second sputtering material, wherein the second sputtering material has a higher sputtering rate than the first sputtering material. The object of the invention is to obtain a particularly uniform coating. This is achieved by molding the inserts (20) made of the second sputtering material such that the lengths (D1, D2) of the inserts, measured in a direction parallel to the surface (14), increase in the depth direction (T) from the surface (14) to the base (12).

Description

Technical Field

[0001] This invention relates to sputtering targets, coating systems, and coating methods. Background Technology

[0002] Sputtering techniques utilize sputtering targets, specifically for coating substrates. In this process, the sputtering target sputters particles by bombardment. The sputtered components from the target enter the gas phase and can thus be used as materials, for example, for surface coatings.

[0003] In the case of PVD coating method using cathode sputtering, the sputtering target is connected as the cathode in the coating chamber of the coating system, and sputtering is performed by means of positively charged particles, especially gases and / or metal ions.

[0004] Besides sputtering targets comprising only one material, sputtering targets comprising multiple materials, particularly different metals, are also known. In this regard, in particular, a design is known in which the sputtering target comprises a plate made of a first material and has holes in the plate, wherein a plug comprising another material is inserted into the holes.

[0005] For example, US 6,852,201 discloses a sputtering component for performing a PVD coating method, wherein sputtering occurs by means of bombardment with gas ions and applies a layer comprising multiple metallic elements to a substrate. The sputtering component includes a titanium base plate having holes into which aluminum plugs are pressed. Aluminum is sputtered at a higher rate than titanium, and therefore the aluminum plugs include concave bends on their exposed surfaces relative to the base plate.

[0006] DE 29 40 369A1 discloses a target for sputtering at least two different metallic materials. A plate made of the material to be sputtered includes a continuous hole with a circular cross-section, into which a bolt made of a second material to be sputtered is inserted via a secure fit. The bolt includes a thickened end that engages in an enlarged end region of the hole, which is designed as a countersunk hole. Summary of the Invention

[0007] The objective can be considered as proposing a sputtering target, particularly for use in cathode sputtering, which achieves a particularly uniform coating.

[0008] This objective is achieved by the sputtering target according to claim 1, the coating system according to claim 14, and the coating method according to claim 15. The dependent claims relate to advantageous embodiments of the invention.

[0009] The sputtering target according to the present invention includes a base plate and a target plate fixed to the base plate. The target plate includes a plurality of inserts arranged in recesses formed on the surface of the target plate.

[0010] The base plate and / or target plate are preferably planar and / or rectangular. The base plate and target plate preferably have at least substantially the same dimensions. The insert is preferably shaped such that it properly fills the recess, which, where applicable, has a recessed portion with a concavely curved surface. The recess and the insert fitted within it can have any desired cross-sectional shape, such as circular, triangular, rectangular, square, polygonal, elliptical, etc. Examples of inserts with various cross-sectional shapes are explained below.

[0011] The target plate includes a first sputtering material and at least some of the inserts, more preferably most of the inserts, and particularly preferably all of the inserts include a second sputtering material. The sputtering material should be understood to mean a solid material that can be used in sputtering methods, and especially coating methods. It is preferably a metal, particularly a pure metal, but other materials, such as carbon, can also be used. Examples of sputtering materials are given below.

[0012] The target plate and the plug are made of different materials. 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%, and even 100% higher than the first sputtering material. As is known to those skilled in the art, sputtering rate is a material-related parameter specifying the average number of target atoms emitted per incident ion during the sputtering process. Therefore, in terms of regions with uniformly impacting ions, there is a higher sputtering erosion rate at the insert made of the second sputtering material compared to the target plate.

[0013] According to the invention, at least some, preferably most, and particularly preferably all of the inserts made of the second sputtered material have a shape in which the length measured in a measurement direction parallel to the surface continuously increases in the depth direction from the surface to the base plate. This should at least be understood to mean that, in a given insert, the insert has a first length at a first shallower depth in the measurement direction and a second length at a second larger depth in the measurement direction, the second length always being greater than the first length. Thus, the magnitude of the length increases in a strictly monotonic manner in the depth direction. Preferably, the corresponding cross-sectional area of ​​the insert also increases in the depth direction in a corresponding manner.

[0014] In the following text, reference is made to the term “conical” or alternatively “circular” as sometimes used for the enlarged shape of inserts; however, it is not limited to conical or alternatively wedge-shaped shapes, i.e., it also means circular cross-sectional shapes and / or continuous linear routes, although the latter is preferred.

[0015] The tapered shape of the insert has been shown to be advantageous in obtaining the most uniform composition of sputtered material in every case throughout the entire service life of the sputtering target. When used in a coating system, the resulting coating consists of the sputtered components of the material. The inventors have determined that, with increasing wear on the cylindrical inserts of conventional sputtering targets, the proportion of the second sputtered material forming the insert decreases relative to the proportion of the first sputtered material forming the target plate.

[0016] By means of the sputtering target according to the invention, this tendency is counteracted, such that changes in the relative proportions of the second sputtering material are preferably at least partially compensated, or ideally at least substantially completely compensated. Therefore, when used in a coating system, a more uniform layer composition can be achieved throughout the entire service life of the sputtering target.

[0017] Inserts whose dimensions increase with depth can be implemented using various designs. For example, the insert may include one or more stepped portions in its longitudinal section, at which the length of the insert increases sharply in the measuring direction. According to the invention, the length of this shape increases continuously, i.e., steadily, in the depth direction, preferably linearly, such that in the case of a circular cross-section, a truncated pyramidal shape is produced, for example, at least partially, or in the case of a rectangular cross-section or, alternatively, a square cross-section, a truncated pyramidal shape is produced. However, a non-linear increase in length in the depth direction is also conceivable. Particularly preferred is that the insert is shaped as a continuous cone or pyramid.

[0018] All inserts made from the second sputtered material can have the same shape and size. However, the shapes, especially the tapers and dimensions, of different inserts can also differ from one another. The corresponding embodiments are explained below.

[0019] In the preferred case of a linear increase in the outer contour, when viewed in a longitudinal section of the insert, compared to a square or cylindrical shape, at least in one portion of the respective insert, the outer contour can extend obliquely, i.e., at a conical angle. This conical angle can, for example, range from 1° to 20°. Since the depth direction extends perpendicularly to the surface here, the angle formed between the edge in question and the surface is, for example, 70° to 89°. Preferably, it is a conical angle of 4° to 15° (corresponding to an angle of 75° to 86° between the edge and the surface); particularly preferably, it is a conical angle of 6° to 12° (an angle of 78° to 84° between the edge and the surface). As explained below, the conical angle of different inserts of the target can be different.

[0020] The preferred increase in the cross-sectional area of ​​the insert varies in different embodiments. Preferably, the cross-sectional area increases by 4% to 40% over a distance of 5 mm in the depth direction, more preferably 8% to 35%, and particularly preferably 15% to 30%. For inserts with a circular cross-sectional area, a slightly lower value of 8% to 30%, and particularly preferably 15% to 25%, is preferable.

[0021] The aforementioned specifications for the taper have proven advantageous, particularly for material pairs in which the second sputtering material has a sputtering rate that is 50% to 150% higher than that of the first sputtering material.

[0022] The base plate and target plate are preferably positioned planarly, one directly on top of the other. According to a preferred embodiment, the base plate may include recesses, preferably formed on the target-facing surface of the base plate, but not completely penetrating the base plate. Some, several, or preferably all inserts made of a second sputtering material preferably protrude into the recesses in the base plate, and more preferably can thus at least substantially completely fill the base plate. Therefore, the target plate material can be utilized in an improved manner because the sputtering target can be used for a longer period, while the base plate material is not sputtered to a large extent.

[0023] The base plate serves two purposes: firstly, to mechanically hold and secure the sputtering target, and secondly, to ensure good heat distribution and dissipation. Preferably, the base plate is entirely or at least primarily made of at least substantially pure copper or a copper alloy. The base plate may include fixing elements or engagement structures for fixing elements, such as holes for engaging fixing elements.

[0024] Specifically, the first and second sputtering materials can be selected from the group consisting of C, B, Al, Si, and elements from Groups 4 to 6 of the periodic table according to IUPAC (1988), either in their pure form or as compounds, alloys, or sintered materials. In a particularly preferred embodiment, the material pair of the first and second sputtering materials can be, for example, titanium / aluminum.

[0025] The target plate and / or base plate are preferably rectangular, particularly elongated, meaning that the length is greater than three times its width, and preferably greater than five times its width. The width can be, for example, in the range of 50 mm to 200 mm, preferably in the range of 70 mm to 150 mm. The length can be, for example, in the range of 200 mm to 1000 mm, preferably in the range of 300 mm to 700 mm. Compared to its length and width, the thickness of the target plate is preferably relatively low and can preferably be, for example, in the range of 3 mm to 30 mm, particularly preferably in the range of 5 mm to 15 mm.

[0026] The insert can be arranged in an annular region on the target plate, that is, along a closed band around the center of the target plate. "Annular" does not necessarily mean circular. In fact, in the preferred rectangular shape of the target plate, the preferred arrangement of the insert follows an elliptical path, or more precisely, a rounded rectangle.

[0027] The inserts are preferably arranged along a line on the target plate, wherein, in each case, successive inserts are arranged offset in a lateral direction from the line. This arrangement has proven advantageous in allowing a relatively large number of inserts along the main region subjected to load during cathode sputtering.

[0028] Inserts of different shapes and / or sizes can be used and can be arranged at different locations on the target plate. In particular, this can be advantageous if different sputtering conditions arise depending on the location on the target plate, for example, if different sputtering conditions arise due to different magnetic field strengths when the sputtering target is positioned on a magnetron cathode. In this way, any non-uniformity can be compensated for. For example, inserts with different cross-sectional areas, particularly different diameters, and / or inserts with larger or smaller tapers can be used. For example, in the case of a rectangular target plate, a first type of insert with a first size and taper can be arranged along the long side of the target plate, and a second type of insert can be arranged on the narrow side. In this way, the effects of position-dependent different sputtering erosion caused by potentially non-uniform ion impacts can be compensated for, making the composition of the eroded material as uniform as possible along the length of the sputtering target. This non-uniform erosion distribution can be addressed by inserts arranged in a particularly loaded first region of the target, which has no taper or a smaller taper compared to, for example, a less loaded second region of the target.

[0029] When using a rectangular target on an unbalanced magnetron cathode, it has been shown that different regions of the target experience different loads depending on the type of electrical excitation. Operation with direct current (DC) voltage results in greater sputtering erosion on the narrow sides, and operation according to the HIPIMS method (High Power Pulsed Magnetron Sputtering) results in greater erosion in the center of the longitudinal sides. Therefore, in the case of using the HIPIMS method, for example, a target can be configured such that the insert, for example, arranged centrally along the longitudinal side, has no taper or a smaller taper in a length region of, for example, 100 mm to 350 mm, preferably 200 mm to 300 mm, compared to the insert on the narrow side.

[0030] Although inserts with circular cross-sections are known and have been tried and tested, it has been shown that with a significant taper, i.e., an increase in diameter in the depth direction, it may be difficult to achieve a sufficiently dense arrangement of inserts to obtain a high surface area ratio of the second sputtered material. According to preferred embodiments, inserts with a strip-shaped cross-section are therefore particularly useful. This should be understood to mean a cross-sectional shape in which the maximum longitudinal dimension, i.e., the length, is significantly greater than the dimension transverse to the length, i.e., the width. The length of the strip-shaped insert preferably corresponds to at least twice the width, and preferably at least three times the width. Even longer designs have proven advantageous, in which the length / width ratio corresponds to at least 4, 5, 8, or 10. Preferably, the strip is at least substantially rectangular, i.e., having two long edges that are at least substantially parallel. The ends may preferably be rounded. With the aid of the strip-shaped insert, a relatively large portion of the area of ​​the sputtering target surface can be readily provided with the second sputtered material.

[0031] The strip insert may have a width of, for example, 5 mm to 20 mm, preferably 8 mm to 16 mm, and particularly preferably 10 mm to 15 mm on its upper side. The length may depend on the arrangement within the rectangular target plate, allowing for the use of shorter inserts in transverse or diagonal arrangements and longer inserts in longitudinal arrangements. In shorter variations, for example, the length may be 20 mm to 100 mm, preferably 25 mm to 80 mm, and particularly preferably 30 mm to 50 mm. In longer variations, the length may, for example, reach 500 mm.

[0032] The strip inserts may be tapered because their length and / or width increase in the depth direction. Preferably, both width and length increase.

[0033] The strip inserts can preferably be arranged parallel to each other. An oblique, diagonal arrangement of the inserts on the rectangular target surface has proven particularly advantageous, wherein the inserts are aligned with the longitudinal axis and / or lateral edge of the rectangular target surface at an angle preferably 20° to 70°, particularly preferably 30° to 60°, and especially 45° + / - 10°. This allows for good uniformity of the distribution of the first and second sputtered materials on the sputtering target surface.

[0034] The present invention also relates to a coating system in which a vacuum is generated in a coating chamber by means of suitable means in a manner known per se, and a substrate to be coated may be arranged in the coating chamber. At least one cathode, preferably multiple cathodes, particularly a magnetron cathode, is arranged in the coating chamber. A sputtering target according to any one of the preceding claims is mounted on at least one cathode, preferably multiple cathodes, or all of the cathodes.

[0035] Finally, the present invention relates to a coating method in which a sputtering target according to the invention is sputtered in a vacuum by means of cathode sputtering and a coating of the sputtering components of the sputtering target is applied to a substrate. Attached Figure Description

[0036] In the following description, embodiments of the invention will be described in more detail with reference to the accompanying drawings, in which:

[0037] Figure 1 This is a perspective view of a first embodiment of a sputtering target with a partially inserted insert;

[0038] Figure 2 Shown in plan view Figure 1 Sputtering target;

[0039] Figure 3 It is along Figure 2 A view of the longitudinal section of the target through which line A..A passes;

[0040] Figure 4 It shows Figure 3 An enlarged view of region B, which illustrates the shape of the insert according to the first embodiment of the sputtering target;

[0041] Figure 5 The coating system is illustrated in a schematic diagram;

[0042] Figure 6 This is a plan view of a second embodiment of a sputtering target with an inserted insert;

[0043] Figures 7a to 7c It is based on Figure 6 A view of the insert of the sputtering target;

[0044] Figure 8 This is a plan view of a third embodiment of a sputtering target with an inserted insert;

[0045] Figure 9 It is a graph showing the erosion progress of the sputtered material relative to the sputtering target;

[0046] Figure 10 , Figure 11 These are plan views of the fourth and fifth embodiments of a sputtering target with an inserted insert; Detailed Implementation

[0047] The accompanying drawings should be understood as illustrative and not necessarily drawn to scale.

[0048] Figure 1 A first embodiment of the sputtering target 10 is shown.

[0049] The sputtering target 10 has a flat rectangular shape. The sputtering target 10 includes a rectangular base plate 12 made of copper and a target plate 14 made of a first sputtering material disposed on the rectangular base plate 12. As an example, the first sputtering material is pure titanium in this case.

[0050] A recess 18 is provided on the front surface 16 of the target plate, and an insert 20 made of a second sputtering material is inserted into the recess 18. As an example, the second sputtering material is pure aluminum in this case. The insert 20 is also referred to as a plug.

[0051] exist Figure 1 To aid understanding, the right half of the sputtering target 10 shows a recess 18 without the insert 20 inserted, while the left half shows a recess 18 with the insert 20 inserted. In practice, the insert 20 is inserted into each of the recesses 18 in the sputtering target 10 such that the recess 18 is completely filled or at least mostly filled. In each case, the upper side of the insert 20 forms a continuous flat surface with the surface 16 of the target plate 14, or alternatively, abuts the surface 16 but has a concave upper recess (not shown).

[0052] Sputtering target 10 in Figure 2 The image is shown in plan view. Recesses 18 and inserts 20 inserted into said recesses 18 are arranged in a ring along a circumferential band on surface 16, the circumferential band having a narrow, elongated rectangular shape with distinctly rounded corners. The continuous inserts 20 are arranged at least along the long edge of the sputtering target 10, laterally offset relative to each other in an alternating manner and closely continuous, such that their edges are almost in contact.

[0053] At the corner, the target plate 14 includes a recess, and the base plate 12 located below the recess includes screw holes for securing the sputtering target 10 to the cathode of the coating system, as will be described below. Figure 5 This is for explanation. Furthermore, the target plate 14 and the base plate 12 include a row of centrally located holes, which are also used for attachment.

[0054] Figure 3 Along Figure 2 The longitudinal section of line A..A passing through the sputtering target 10 shows the arrangement and shape of the base plate 12, target plate 14, recess 18, and insert 20. Figure 4 The enlarged diagram shows Figure 3 Region B.

[0055] In the example shown, the inserts 20 each have the same shape. Each insert 20 is shaped as a truncated cone with a smaller upper diameter D1 and a larger lower diameter D2 at surface 16. The lateral dimension of the diameter, measured here, increases linearly from diameter D1 to diameter D2 in the direction of measurement parallel to surface 16, extending at a right angle from surface 16 toward base plate 12. Therefore, the cross-sectional area of ​​the insert 20, measured parallel to surface 16 in each case, increases accordingly.

[0056] exist Figure 4 In the enlarged longitudinal section, with respect to the outline of the insert 20 shown, it can be seen that the side edges of the adjacent recess 18 of the insert 20 extend obliquely, that is, obliquely with a taper angle α relative to the vertical and with an angle β relative to the surface 16 (where β = 90° - α is obviously effective).

[0057] In the preferred exemplary embodiment shown, angle α is approximately 8° and therefore angle β is approximately 82°.

[0058] Figure 4 It is also shown that the insert 20 extends further in the depth direction than the extension corresponding to the thickness T1 of the target plate 14, that is, it extends into the recess 22 in the base plate 12. The base plate 12 here has a thickness T2 and the insertion 20 extends T3 in the base plate 12.

[0059] In a preferred embodiment, the length or, more precisely, the depth (T1+T3) of the insert 20 is approximately 4 mm to 20 mm, preferably approximately 7 mm. The upper diameter D1 of the insert 20 is, for example, in the range of 10 mm to 20 mm, and preferably approximately 15 mm, and the lower diameter D2 is, for example, 5% to 20% larger than D1, preferably approximately 13% larger.

[0060] Figure 5 A coating system 30 with a vacuum chamber 32 is schematically shown, in which, as an example, four cathodes 40, designed as unbalanced magnetrons, are arranged around a substrate stage 38. In each case, each cathode 40 is equipped with a sputtering target 10.

[0061] The device 34 for generating a vacuum (pump system) and the device 36 for supplying process gas, as well as the reactive gas if applicable, are connected to the vacuum chamber 32.

[0062] The cathode 20, substrate stage 38 and anode 44, which are also arranged in the vacuum chamber 32, are connected to the power supply system 42.

[0063] For example, coating system 30 can be constructed and operated according to the method disclosed in the applicant's WO 98 / 46807. The contents of this document, particularly regarding the electrical configuration of the components of the illustrated coating system 30 and the process during coating, are incorporated herein.

[0064] In vacuum chamber 32, plasma is generated between cathode 40 and anode 44 by means of voltage through power supply system 42, causing sputtering target 10 to be sputtered. As a result, the substrate arranged on substrate stage 38 is coated with the components sputtered by sputtering target 10.

[0065] During operation of the coating system 10, material is eroded primarily from the surface 16 of the sputtering target 10 along erosion channels that extend in a circumferential manner on the sputtering target along the arrangement of the inserts 20 (see [link]). Figure 2 The material is eroded from both the relevant exposed surface of the target plate 14 and from the insert 20.

[0066] However, depending on the corresponding sputtering rate of the material, the erosion is not uniform but different for the first sputtering material, which is titanium in this case, and for the second sputtering material, which is aluminum in this case.

[0067] The following examples provide sputtering rates for some materials at 600 eV (for sputtering with Ar ions):

[0068]

[0069] Therefore, for the preferred titanium / aluminum material pair, the sputtering efficiency of the second sputtering material is approximately 100% higher than that of the first sputtering material, titanium.

[0070] After a certain operating time, the higher sputtering rate of the second sputtering material constituting the insert 20 causes the surface 16 of the sputtering material to no longer be flat, but rather the insert 20 to deepen in the form of recesses. These recesses, in turn, result in partial shielding against impacting ions, making the corresponding ratio of the first and second sputtering materials, considering the aforementioned sputtering rates, not directly determined by the cross-section of the insert 20 and the surface of the target plate 14, but rather by a more complex situation. However, in any case, in comparisons of cylindrical inserts 20 not according to the invention, the proportion of the second sputtering material in the vacuum chamber 32, or more precisely, the proportion of the coating formed on the substrate, has been shown to decrease over the entire service life of the sputtering target 10.

[0071] exist Figure 3 and Figure 4In the case of the tapered shape of the insert 20 shown, the dimension of the insert increases in the depth direction, and progressive erosion gradually exposes a gradually increasing area. This offsets or, ideally, completely compensates for the decrease in the proportion of the second sputtered material.

[0072] Although all inserts 20 have the same shape in the above embodiments of the sputtering target 10, the shapes of the individual inserts 20 of the same sputtering target 10 may also be different from each other. In particular, the inserts 20 may have different tapers (i.e., different taper angles), or the inserts 20 may have a cylindrical shape, i.e., no taper.

[0073] Therefore, as an alternative embodiment (not shown), a sputtering target 10 is proposed, which has the same shape as the target plate 14 and the same number and arrangement of inserts 20 as the sputtering target 10 shown, wherein the cylindrical inserts 20, i.e., the non-tapered inserts 20, are still arranged at a distance of, for example, 250 mm from the center of the longitudinal side of the target plate 14. This target is particularly suitable for operation according to the HIPIMS method, where there is more erosion at the center of the longitudinal side.

[0074] Figure 6 as well as Figures 7a to 7c A sputtering target 110 and its insert 120 according to a preferred second embodiment are shown. The sputtering target 110 according to the second embodiment largely corresponds to the sputtering target 10 according to the first embodiment; the same components are provided with the same reference numerals. Similar to the sputtering target 10, the sputtering target 110 includes a rectangular target plate 14, wherein a base plate 12 is arranged below the rectangular target plate 14. Figure 6 (Not visible in the middle).

[0075] In the following text, only the differences between the implementation methods will be mentioned.

[0076] The second embodiment differs from the first embodiment in that the cross-sectional shapes of the recess 118 and the insert 120 received in the recess 118 are different. Each insert has a strip-shaped, i.e., long rectangular cross-section, but with rounded ends.

[0077] The recess 118 and the insert 120 are tapered, meaning their dimensions increase in the depth direction T. At surface 16, the insert 120 has a length L1 and a length L2 at its lower end that is greater than L1. Transversely to the length, the width B2 at the lower end is also greater than the width B1 at surface 16. Due to their elongated shape, the lengths L1 and L2 are significantly greater than the associated widths B1 and B2 in each case, and in this case, approximately ten times larger. The different insert 122, i.e., the shortened insert, is received in the corresponding recess only at the longitudinal end of the target plate 14.

[0078] 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 from width B1 to width B2 in the depth direction T, such that when viewed in the longitudinal direction of the insert 120, the sidewalls extend at an angle β1. At the same time, the length of the insert 120 increases from length L1 to length L2 in the depth direction T, such that when viewed in the transverse direction of the insert 120, the sidewalls extend at an angle β2. Therefore, the cross-sectional area of ​​the insert 120 increases from surface 16 along the depth direction T from area L1×B1 (parallel to surface 14) to area L2×B2 (wherein, rounding is not considered in this calculation).

[0079] For different implementations, the dimensions L1, L2, B1, B2, β1, and β2 can be different. In particular, it is possible for L1 = L2 or B1 = B2, that is, for example, the insert 120 can be tapered only in the longitudinal or transverse direction. In particular, from a manufacturing point of view, it can be demonstrated that providing a taper only in the transverse direction and not in the longitudinal direction (i.e., L1 = L2) is simpler, because the effect of the taper in the transverse direction is more significant in any case.

[0080] In a preferred exemplary embodiment, the insert 120 can be characterized, for example, by the following values:

[0081] L1 = 95mm

[0082] L2 = 95mm (at a depth T of 5mm)

[0083] B1 = 15mm

[0084] B2 = 18mm

[0085] β1 = 73.3° (at a depth T of 5 mm)

[0086] β2 = 90°.

[0087] This results in an increase of approximately 20% in cross-sectional area at a depth of 5 mm compared to surface 16.

[0088] according to Figure 6 In one embodiment, the elongated inserts 120 extend parallel to each other on the surface 16, aligned diagonally with respect to the edge of the target plate 14, in which case the inserts 120 extend at an angle of approximately 45°.

[0089] Compared to the circular cross-section of the insert 20 according to the first embodiment, the elongated shape of the insert 120 allows for a higher proportion of the material of the insert 120 (here: aluminum) relative to the material of the target plate 114 (here: titanium) at surface 16. Most importantly, due to the taper 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 more easily without causing problems with the insertions 120 being placed adjacent to each other.

[0090] Figure 8 A sputtering target 210 according to a third embodiment is shown. The sputtering target 210 according to the second embodiment largely corresponds to the sputtering target 110 according to the second embodiment; in this case, the same parts are also provided with the same reference numerals. Hereinafter, reference will only be made to the differences between the embodiments.

[0091] In the third embodiment, the recess 218 and the insert 220 inserted into the recess 218 are also elongated, but with a width-to-length ratio of approximately 1:4, making the recess 218 and insert 220 significantly shorter. The inserts 220 are also aligned diagonally at approximately 45° relative to the edge and arranged in two parallel rows along the longitudinal edge of the target plate 14. The inserts 220 are also tapered, meaning their length and / or width increase in the depth direction T (in...). Figure 8 (Not shown in the image).

[0092] according to Figures 7a to 7c The designation of insert 120 also applies to insert 220, meaning that dimensions L1, L2, B1, B2, β1, β2 also apply to the increase in shape and size in the depth direction T. According to a preferred exemplary embodiment, these dimensions can be selected as follows:

[0093] L1 = 31mm

[0094] L2 = 34mm (at a depth T of 5mm)

[0095] B1 = 15mm

[0096] B2 = 18mm (at a depth T of 5mm)

[0097] β1 = 73.3°

[0098] β2 = 73.3°.

[0099] This results in an increase of approximately 32% in cross-sectional area at a depth of 5 mm compared to surface 16.

[0100] Figure 9 Results of coating tests using various sputtering targets 210 according to the third embodiment are shown. As described above, a coating is applied in the system 30 by means of the sputtering target 210, which includes a target plate 14 made of titanium and an insert 220 made of aluminum. The aluminum content in the resulting layer (in atomic percent of metal layer content) and the erosion of the sputtering target 210 (in mm) are shown.

[0101] exist Figure 9 The diagram shows three different curves for different tapers of insert 220, each represented by the area ratio between the cross-sectional area at surface 16 and the cross-sectional area at the lower end. Thus, the lowermost line, represented by 1:1, indicates an insert whose dimensions do not increase in the depth direction (comparative example); the two upper lines show curves for a low taper (1:1.2, i.e., a 20% increase in cross-sectional area at a depth of 5 mm) and a higher taper (1:1.3, i.e., a 30% increase in cross-sectional area at a depth of 5 mm).

[0102] In the comparative example with a non-tapered insert (line 1:1), when the sputtering target was etched to a depth of 5 mm, the Al content decreased from approximately 58 atomic percent initially to less than 50 atomic percent. Even a taper with a 20% increase in cross-sectional area significantly reduced the decrease in Al content to approximately 54%. Tapers with a 30% or greater increase in cross-sectional area again produced a decrease in Al content, however, this time by a much smaller margin.

[0103] Figure 10 and Figure 11 Sputtering targets 310 and 410 according to the fourth and fifth embodiments are shown. The sputtering targets 310 and 410 according to the fourth and fifth embodiments largely correspond to the sputtering targets 110 and 210 according to the previously described embodiments; in this case, the same components are also provided with the same reference numerals. Hereinafter, only the differences between the embodiments will be mentioned.

[0104] In the fourth and fifth embodiments, the recesses 318, 418 and the inserts 320, 420 inserted into the recesses 318, 418 are not arranged diagonally, but are parallel to the edge of the target plate 14; Figure 10 In the examples, they are parallel to the narrow sides, while Figure 11 They are parallel to the long side. In this case, inserts 320 and 420 are also tapered, meaning their length and / or width increase in the depth direction T (in the depth direction T). Figure 10 and Figure 11(Not shown in the image).

[0105] In summary, it has been shown that the taper of the inserts in the sputtering target can be used to homogenize the relative proportions of coating materials in the resulting layer. This taper can be provided for inserts 20, 120, 220, 320, 420 with different cross-sectional shapes and arrangements in the target plate 14.

Claims

1. A sputtering target (10), comprising, - Base plate (12). - Target plate (14), which is fixed on the base plate (12) and is made of a first sputtering material, the target plate (14) having a surface (16) and a plurality of first recesses (18) formed in the surface (16). - a plurality of inserts arranged in the first recess (18), wherein At least some of the inserts are made of a second sputtered material. - Wherein, the second sputtering material has a higher sputtering efficiency than the first sputtering material. - and wherein at least a portion of the insert made of the second sputtering material is shaped such that the length (D1, D2) of the insert, measured in a measurement direction parallel to the surface (16), increases continuously in the depth direction (T) from the surface (16) to the base plate (12).

2. The sputtering target according to claim 1, wherein, - At least some of the inserts made of the second sputtered material are shaped to be at least partially conical or pyramidal.

3. The sputtering target according to claim 1 or 2, wherein, - At least some of the inserts made of the second sputtered material are shaped such that their cross-sectional area increases by 4% to 40% along the depth direction (T) at a depth of 5 mm.

4. The sputtering target according to claim 1 or 2, wherein, - At least some of the inserts made of the second sputtered material are shaped such that: in the longitudinal section, the edges extend at an angle of 70° to 89° relative to the surface (16).

5. The sputtering target according to claim 1 or 2, wherein, - The base plate (12) includes a second recess (22). - And the insert made of the second sputtered material protrudes into the second recess (22) in the base plate (12).

6. The sputtering target according to claim 1 or 2, wherein, - The first sputtering material is titanium and the second sputtering material is aluminum.

7. The sputtering target according to claim 1 or 2, wherein, - The base plate (12) is entirely or at least primarily made of copper or a copper alloy.

8. The sputtering target according to claim 1 or 2, wherein, - The insert is arranged in the annular region on the target plate (14).

9. The sputtering target according to claim 1 or 2, wherein, - The insert is arranged along a line on the target plate (14), wherein the insert is arranged in each case to be offset in a direction laterally to the line.

10. The sputtering target according to claim 1 or 2, wherein, - The two inserts arranged at different positions on the target plate (14) have different shapes and / or sizes.

11. The sputtering target according to claim 1 or 2, wherein, - The insert has a strip-shaped cross-section with a length corresponding to at least twice its width.

12. The sputtering target according to claim 11, wherein, - The length and / or the width increase in the depth direction (T).

13. The sputtering target according to claim 11, wherein, - The target plate (14) is rectangular. - And the insert is aligned at an angle of 20° to 70° with respect to the longitudinal edge and / or lateral edge of the target plate (14).

14. A coating system, comprising: - Coating chamber (32). - A device (34) for generating a vacuum in the coating chamber (32). - A means (38) for arranging the substrate to be coated in the coating chamber (32). - and at least one cathode (40), said at least one cathode (40) being arranged in the coating chamber (32), - wherein the sputtering target (10) according to any one of claims 1-13 is mounted on the cathode (40).

15. A coating method, wherein, - The sputtering target (10) according to any one of claims 1 to 13 is sputtered in a vacuum by means of cathode sputtering, and a coating of the sputtering components of the sputtering target (10) is applied to the substrate.

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