Low-oxygen content ag alloy sputter target

Abstract

The invention relates to a sputter target with a low oxygen content. The sputter target is based on silver (Ag) and comprises a small amount of alloying elements selected from the group consisting of Mg, Al, Si, Ca, Sr, Sc, Y, rare earth metals, Ti and Ge and combinations thereof. The invention further relates to a layer prepared using the sputter target and a method for preparing the sputter target.

Description

Technical Field

[0001] This invention relates to a sputtering target with low oxygen content. The sputtering target is based on silver (Ag) and contains small amounts of alloying elements selected from Mg, Al, Si, Ca, Sr, Sc, Y, rare earth metals, Ti, and Ge, and combinations thereof. The invention also relates to a layer prepared using the sputtering target, and a method for preparing the sputtering target. Background Technology

[0002] Silver-based alloys are known and commonly used to prepare layers for glazing applications, such as coatings for architectural glass, or as reflective layers in optical storage media and displays. Layers are typically prepared using sputtering targets made of the appropriate alloys.

[0003] For example, European patent application EP 2 647 737 A1 describes alloy sputtering targets based on silver and at least one other component selected from indium (In), tin (Sn), antimony (Sb), or bismuth (Bi). These alloys are characterized by high corrosion resistance and are particularly suitable for preparing display layers. The application of AgAl alloys in glass coatings is known. For example, international application WO 2021 / 214107A1 describes the use of AgAl alloys as a metallic layer in multilayer solar control glass structures, such as window glass or vehicle glass.

[0004] However, silver-based alloys and corresponding sputtering targets containing such alloys remain needed. Silver alloy sputtering targets are particularly needed for preparing coatings on glass and display layers. In such applications, obtaining products with good and uniform adhesion properties and uniform layer thickness is crucial.

[0005] Furthermore, avoiding arc discharge during sputtering is desirable and important. Therefore, the alloys contained in the sputtering target must have low sensitivity to this effect. Summary of the Invention

[0006] sputtering target The purpose of the above discussion is achieved by providing a sputtering target as defined in the appended claims.

[0007] Therefore, the present invention relates to a sputtering target comprising or composed of an AgX alloy, the AgX alloy being composed of Ag and 0.06 at.-% to 0.50 at.-% X, wherein X is at least one alloying element selected from the group consisting of Mg (magnesium), Al (aluminum), Si (silicon), Ca (calcium), Sr (strontium), Sc (scandium), Y (yttrium), rare earth metals, Ti (titanium), and Ge (germanium).

[0008] The rare earth metals referred to in this article are the elements La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), and Lu (lutetium). Among them, La (lanthanum) and Ce (cerium) are preferred alloying elements among rare earth metals.

[0009] Surprisingly, it has been found that when the sputtering target according to the invention has high uniformity, the content of at least one alloying element X in the sputtering target is as low as 0.50 at.-% or less, making it particularly suitable for use as a coating and layer (e.g., thin film) in glass and displays.

[0010] The AgX alloy is composed of Ag and X, wherein X is at least one alloying element selected from the group consisting of Mg, Al, Si, Ca, Sr, Sc, Y, rare earth metals, Ti, and Ge, and combinations thereof. Preferably, X is at least one alloying element selected from the group consisting of Mg, Al, Si, Ca, Sr, Sc, Y, La, Ce, Ti, and Ge, and combinations thereof; more preferably selected from Al and / or Ti; and most preferably Al.

[0011] The selected alloying element X has good oxygen affinity, thus exhibiting excellent adhesion to glass. Therefore, it forms a stable layer with strong adhesion and corrosion resistance on the glass surface. It is speculated that this reactive element can inhibit island growth, thereby enabling the preparation of smoother layers even at lower film thicknesses.

[0012] The content of X in the AgX alloy is from 0.06 at.-% to 0.50 at.-%, preferably from 0.07 at.-% to 0.30 at.-%, and more preferably from 0.08 at.-% to 0.20 at.-%. It should be understood that if X contains more than one alloying element, this content applies to the sum of all alloying elements. Surprisingly, such a low content of at least one alloying element X is sufficient to obtain these improved properties.

[0013] In one specific embodiment, the AgX alloy is composed of Ag and Al, wherein the Al content is from 0.07 at.-% to 0.30 at.-%, more preferably from 0.08 at.-% to 0.20 at.-%.

[0014] The content of the alloying element X is usually low, which has the advantage that the conductivity and reflectivity of the film can be maintained at a high level, and the content of oxides derived from these alloying elements X in the alloy is extremely low.

[0015] However, preparing alloys with such low alloying element content is generally difficult for at least two reasons: i) It is difficult to achieve a uniform distribution of alloying elements in the host metal. Clearly, sputtering targets containing more uniformly distributed alloys can achieve more uniform layer sputtering, thus ensuring consistent performance across the entire size range. Typical target sizes, ranging from 1.5m to 4m, are planar or tubular, whether for display or architectural glass applications.

[0016] ii) Achieving the required doping level is quite difficult, especially for large Ag melts and such small amounts of additive. Due to the high oxygen affinity of alloying element X, it is easily oxidized during smelting and casting, thus transforming into an inert oxide rather than a dissolved metal.

[0017] This invention provides an AgX alloy sputtering target with an oxygen content of less than 50 ppm-wt., more preferably less than 20 ppm-wt., even more preferably less than 10 ppm-wt., and most preferably less than 5 ppm-wt. The method for determining the oxygen content is described below, and the oxygen content reflects the oxide content in the AgX alloy.

[0018] A lower oxide content is more conducive to avoiding arc discharge and micro-arc discharge in AgX alloy sputtering targets. Otherwise, such discharges would cause spatter, thereby impairing the uniformity and functionality of the deposited layer. No such phenomena were observed during the preparation of layers using the sputtering target of this invention.

[0019] Crucially, at least one alloying element X is introduced predominantly in a metallic state into the AgX alloy, i.e., not in oxide form. Studies have found that introducing alloying element X in a metallic state is more advantageous for improving the physical properties of AgX alloys. In particular, when the alloying element is introduced primarily in a metallic state, micro-arcing events are reduced. This further promotes the dissolution and uniform distribution of the alloying element in the AgX alloy, as well as the uniform adhesion of the prepared layer.

[0020] Therefore, in five regions at any location on a scanning electron microscope (SEM) sample, within 1 mm... 2 Within the region, it can be detected in the form of oxides, with a cluster size greater than 1 μm. 2 The number of inclusion clusters of alloying element X is preferably no more than two, more preferably no more than one, and even more preferably none at all, as described in the measurement method below. A smaller number of clusters indicates a higher content of the alloying element existing in the metallic state. No clusters were detected in the sputtering target analyzed in this invention, which means that the alloying element exists in the metallic state.

[0021] Further preferably, at least one alloying element X in the AgX alloy is uniformly distributed. Preferably, the sputtering target is characterized in that the deviation between the X content measured at any location on the sputtering target and the average X content in the sputtering target does not exceed 20%, preferably not more than 10%, for example, 5% or less, wherein both the X content and the average content are determined by inductively coupled plasma optical emission spectrometry (ICP-OES).

[0022] Specifically, the average X content in the sputtering target was determined by ICP-OES, as detailed in the Methods section. (Reference) Figure 1 (It shows a schematic diagram of the target material in Example 1), and the determination of uniform distribution is described below.

[0023] For the purposes of this invention, to determine the preferred uniform distribution, it is sufficient to measure six samples at six different locations (C1-C6) on the sputtering target, provided that these locations are arranged along the length direction of the sputtering target and the spacing between them is at least 1 / 10 of the total length of the sputtering target. In other words, the distance d between adjacent locations is at least 1 / 10 of the total length of the sputtering target.

[0024] If the X content at all six positions does not deviate by more than 20% of the average X content (obtained by averaging the content at these six positions). , Then it is considered that a uniform distribution has been achieved.

[0025] When calculating percentages, it is preferable to use the atomic percentage (at.-%) of the X content in the AgX alloy.

[0026] If X contains more than one alloying element, the above percentages apply to the sum of all alloying elements together, meaning that the content of each element is always considered as part of the sum of the ICP-OES results of the added alloying metals, where the sum is related to determining a uniform distribution.

[0027] To achieve a uniform layer thickness, the average grain size of the AgX alloy is preferably less than 150 μm, for example, in the range of 10 μm to less than 150 μm, and more preferably in the range of 20 μm to 120 μm. This small grain size is particularly advantageous for planar or tubular sputtering targets with a length of 1 m or longer.

[0028] Further preferably, the maximum grain size is less than 300 μm, for example, the grain size ranges from 5 μm to less than 300 μm. Grain size is typically measured according to DIN EN ISO 643 as described below.

[0029] High metallic purity is also crucial for the AgX alloy. The minimum metallic purity requirement for the AgX alloy is 99.9 wt.-% (3N). Preferably, based on the Ag matrix, the metallic purity of the AgX alloy is not less than 99.95 wt.-% (3N5), more preferably not less than 99.99 wt.-% (4N). Metallic purity refers to the purity of a metal or alloy, where only unintentionally added elements are considered impurities. For AgX alloys, X is not considered an impurity (e.g., in AgTi alloys, Ti is not considered an impurity).

[0030] The layers prepared using the sputtering target are characterized by excellent adhesion to substrates (such as glass), which is attributed to the high oxygen affinity of alloying element X in the metallic state and the low oxide content in the AgX alloy. Furthermore, as described above, these layers also exhibit uniform thickness and uniform distribution of alloying element X within the AgX alloy.

[0031] method The present invention also relates to a method for preparing a sputtering target, namely, a sputtering target comprising an AgX alloy composed of Ag and 0.06 at.-% to 0.50 at.-% X, wherein X is at least one alloying element selected from the group consisting of Mg, Al, Si, Ca, Sr, Sc, Y, rare earth metals, Ti and Ge and combinations thereof, wherein the sputtering target may be implemented in any of the above embodiments and possess any of the above characteristics, and the oxygen content of the AgX alloy is less than 50 ppm-wt.

[0032] In preparing sputtering targets, the key is to control the oxide content in the AgX alloy to a low level, and the AgX alloy contains at least one alloying element X that is uniformly distributed in the main metallic state.

[0033] The preferred Ag metal used should generally have a high purity, for example, at least 99.9 wt.-% (3N), preferably at least 99.95 wt.-% (3N5), and more preferably at least 99.99 wt.-% (4N) or higher.

[0034] The alloying element X used preferably has high metal purity, for example, at least 99.5 wt.-% (2N5), preferably at least 99.9 wt.-% (3N), more preferably at least 99.95 wt.-% (3N5) ​​or higher.

[0035] The method according to the invention comprises: heating an Ag metal block (e.g., granules) in an inert container to a temperature range of 980°C to 1200°C under vacuum or inert gas conditions and in the presence of at least one alloying element X to prepare the AgX alloy. In this manner, the AgX alloy melt can be prepared directly without additional steps such as diluting the pre-alloy to the final AgX alloy.

[0036] Surprisingly, it has been found that, according to the method of the present invention, where Ag metal is used as the starting material and alloying element X is directly incorporated into the Ag metal, an alloy with extremely low and highly uniform oxide content can be obtained. Therefore, alloying element X is well distributed in the Ag matrix, while the oxidation degree of alloying element X is minimized.

[0037] It is well known in the art to prepare alloys with such low alloying element contents through a two-step process. Therefore, firstly, an Ag alloy with a relatively high alloying element content is prepared (e.g., an Ag alloy with an alloying element content 10 times higher). In the second step, these alloys are further “diluted” by adding Ag particles to obtain a final Ag alloy with the desired low alloying element content. However, this two-step process increases the risk of oxidation of reactive alloying elements. As a result, the final composition may deviate significantly from the expected composition, or a large amount of alloying element X may be present in the form of oxides. This is particularly disadvantageous because the risk of arcing is greatly increased.

[0038] These drawbacks can be avoided by using the method described in this invention.

[0039] Typically, according to the method of the invention, a melt is provided in which at least one alloying element X is dispersed into an Ag melt. For this process, careful degassing of the vacuum chamber and crucible is preferred. This is particularly advantageous for adding alloying elements X (e.g., Al) that have a high oxygen affinity. The melting process is carried out under vacuum and / or an inert gas atmosphere (e.g., argon).

[0040] The Ag melt is prepared by heating Ag metal blocks (preferably Ag particles) to a temperature range of 980°C to 1200°C, more preferably 1000°C to 1100°C, in an inert and optionally micro-reducing container (e.g., an alumina or graphite crucible). The inert container referred to herein is one capable of withstanding temperatures above 1200°C under vacuum or inert gas conditions without cracking or releasing components into the Ag melt. The inert and optionally micro-reducing container can be, for example, a crucible made of high-purity alumina, graphite, quartz, or a coldhearth crucible.

[0041] In a preferred embodiment, a degassed vacuum chamber and crucible are used for vacuum induction melting, ideally using a diffusion pump.

[0042] The melt can then be poured into a mold (such as a graphite or steel mold). If the melt is allowed to cool and solidify in this manner, a solid molded body can be obtained.

[0043] Typically, particles, chips, flakes, platelets, and / or wire cut-offs are all suitable as blocks of Ag metal and alloy element X. Alloy element X can also exist in the form of a single solid piece, such as wire.

[0044] In some embodiments of this method, the at least one alloying element X is in the form of a solid piece of material with a specified size, preferably in the form of a wire with a specified diameter and a specified length, and the at least one alloying element X is at least partially placed in a volume of the Ag metal pieces, and then the Ag metal pieces and the at least one alloying element X are heated to prepare an Ag melt, wherein the at least one alloying element X is dispersed in the Ag melt.

[0045] At least one alloying element X is dispensed into the Ag melt by melting it from a solid material block, preferably under stirred melt conditions. The solid material block is at least partially placed within the volume of the Ag metal block, preferably at a position perpendicular to the open surface of the Ag metal block volume. It may be completely covered by the Ag metal block volume or partially located outside of it, and is continuously melted out by the prepared Ag melt during the smelting process.

[0046] Solid material parts with specified dimensions include, in particular, wires of alloy element X with specified diameter and specified length, such as high-melting-point metal wires, such as Ti wires used to prepare AgTi alloys.

[0047] If multiple alloying elements are used, they can be added simultaneously or sequentially, with simultaneous addition being preferred.

[0048] In some embodiments of this method, the at least one alloying element X is in block form, and the Ag metal blocks and the at least one alloying element X are prepared in a stacked manner. First, a stack 1 of Ag metal blocks is provided. A stack 2 of at least one alloying element X is placed on stack 1. Subsequently, stack 2 is covered with a stack 3 of Ag metal blocks (stack 1 and stack 3 constitute 100% Ag metal blocks), the Ag metal blocks and the at least one alloying element X are heated to prepare an Ag melt, and the at least one alloying element X is dispersed into the Ag melt.

[0049] In these embodiments, preferably, Ag particles are packed into an inert or slightly reduced crucible (e.g., an alumina or graphite crucible) to form pile 1. Then, small pieces of at least one alloying element X, such as fragments, flakes, or wire cuts of alloying element X (e.g., Al), are placed on top of the Ag particles in the crucible (preferably near the center) to form pile 2, which is then covered with the remaining Ag particles. The crucible is heated to a temperature range of 980°C to 1200°C, and Ag melt slowly forms.

[0050] Preferably, pile 1 comprises more Ag metal blocks (e.g., particles) than pile 3, for example, pile 1 comprises 60% to 90% of the Ag metal blocks used, preferably 65% ​​to 85%.

[0051] In some embodiments of this method, the at least one alloying element X can also be added to the liquid Ag melt via a post-feeding unit.

[0052] For all embodiments of this method, it is preferable to hold the melt at the melting temperature for a sufficient time to allow the alloying element X to be uniformly distributed in the Ag matrix. This dwelling time depends on the total weight of the melt and the stirring during the dwelling. Typical dwell times are 10 to 30 minutes. Induction melting is preferred here because it allows for vigorous stirring. The melt is then cast into a steel or graphite mold. In this way, solid blocks or cylinders of the Ag alloy AgX can be obtained.

[0053] The production method preferably further includes at least one of the following steps, more preferably at least two: a) Hot working, such as rolling, forging, and / or extrusion in a temperature range of 400°C to 800°C. b) Cold working, such as cold rolling, forging, or extrusion. c) Annealing is carried out at a temperature range of 300°C to 450°C for a time range of 30 minutes to 3 hours, depending on the weight of the sheet or tube.

[0054] Suitable additional production steps that can be used are described, for example, in EP 3 168 325 A1.

[0055] The present invention also relates to a sputtering target prepared according to the method described in the present invention, having any of the above-described embodiments and features.

[0056] application The sputtering target according to the present invention can be used to deposit Ag layers that require or are desired to have good adhesion, high uniformity of alloy materials, and low agglomeration tendency.

[0057] For example, Ag alloys can be deposited as layers on glass or in display products. Preferably, such layers serve as reflective layers for visible or infrared radiation. The thickness of these layers can be from a few nanometers to about 1000 nm, for example, 10 nm to 20 nm, or 100 nm to 400 nm.

[0058] Therefore, the present invention also relates to a layer formed by sputtering an AgX alloy from any of the sputtering targets described herein onto a substrate.

[0059] The layer can be formed from an Ag alloy of a (planar or tubular) sputtering target by physical vapor deposition (PVD) (e.g., sputtering, ion beam deposition, pulsed laser deposition, and combinations thereof). Preferably, the layer is deposited by magnetron sputtering. Attached Figure Description

[0060] The present invention will be further described in conjunction with the following embodiments and with reference to the accompanying drawings, wherein: Figure 1 The diagram shows a schematic of a 3750 mm Ag-Al 0.20 at.-% sputtering target, including indicated locations, where samples were collected for Al content determination by ICP-OES; and Figure 2 The image shows a micrograph of a sputtering target sample of Ag-Al 0.20 at.-%. Detailed Implementation

[0061] Test methods The parameters described in this article were tested using the following methods.

[0062] a) Grain size For optical measurements using scanning electron microscopy (SEM) and optical microscopy, sputtering target samples are obtained by cutting the corresponding block from a target plate or hollow cylinder using a water jet, followed by a first milling process.

[0063] The sample was embedded in the resin with the sputtered surface facing upwards, and then polished using a gradually decreasing grit size from 120 to 4000 mesh. Finally, it was polished with diamond paste. Subsequently, the sample surface was etched at 25°C for 60 seconds using a hydrogen peroxide / ammonia solution.

[0064] The method for evaluating grain size is as follows: Take one photograph for each photomicrograph. The magnification is set such that the lines drawn on the photograph of the etched sample cross 8 to 30 grain boundaries.

[0065] Each micrograph was evaluated using the line intersection method (ASTM E112), and the average grain size of each of the 10 samples was calculated. Additionally, the maximum grain size of each of the 10 samples measured using this method was recorded.

[0066] The average grain size M is determined according to DIN EN ISO 643 standard, using the linear intercept method based on the following equation:

[0067] in L: Length of the measuring line p: Number of measuring lines N: Number of grains intercepted by the measured line m: Magnification These values ​​are in 3 The measurements were taken at 3 = 9 different locations, each with three depths: 0 mm, 3 mm, and 6 mm. The arithmetic mean of the 9 measurements was then calculated.

[0068] b) Homogeneity was determined by inductively coupled plasma (ICP-OES) analysis. The uniform distribution of alloying element X in the AgX alloy was determined by obtaining samples from six different locations (C1-C6) on the sputtering target, provided that these locations are along the length of the sputtering target (i.e., the long side direction) and the distance between them is at least 1 / 10 of the total length of the sputtering target. (Refer to...) Figure 1 The distance d between two adjacent positions is at least 1 / 10 of the total length of the sputtering target. For rectangular sputtering targets, the longest side of the sputtering target is considered the length of the sputtering target. For cylindrical sputtering targets, the distance between the two planar end faces of the cylinder is considered the length of the sputtering target.

[0069] The samples were prepared by taking 3 to 10 grams of fragments from each location of the target using a pressure drill, and the content of X was determined by ICP-OES.

[0070] If the X content at all six locations does not deviate from 20% of the average X content, then a uniform distribution is considered achieved. The average X content is determined by the following formula:

[0071] When an AgX alloy contains multiple alloying elements, the total amount of these alloying elements should be considered.

[0072] The same ICP-OES method is used for the routine determination of the average content of alloying elements in any alloy.

[0073] c) Oxygen content determination Fragments (approximately 1 gram) were taken from the sputtering target using a pressure drill, etched with nitric acid, carefully dried, and their oxygen content was determined using the Horiba EMGA-920 system according to standard procedures via the carrier gas method.

[0074] d) Determining the metallic state of alloying elements by SEM Polished samples used for grain size testing were placed in a SEM (scanning electron microscope) to study oxide inclusions. The samples were scanned at high resolution to look for oxide clusters. The presence of such clusters (which are typically absent) was examined using elemental mapping, and it was also determined whether these clusters also showed the fingerprint of alloying element X.

[0075] Specifically, on five arbitrary 1mm samples of the SEM sample 2 The region was analyzed to determine the presence of inclusion clusters of alloying element X in oxide form, with cluster sizes greater than 1 μm. 2 A small number of clusters indicates a higher content of metallic alloying elements. If the number of inclusion clusters in each of the five regions does not exceed two, it indicates that alloying element X is in a high metallic state.

[0076] e) Thickness of sputtered deposit layer Layer thickness was measured using a probe-contact profilometer (such as the KLA Tencor D-500). During sample preparation, the substrate was partially covered with Kapton tape, preventing sputtering in the covered areas. After removing the cover, the layer thickness at the step formed between the coated and uncoated regions could be measured. The diamond probe of the measuring device measured the layer thickness by deflection. The device was calibrated to 1 μm using the included standard. Measurements were repeated at 10 different locations on the sample, and the average value was taken.

[0077] Example Example 1 Preparation of AgAl sputtering targets Two types of AgAl sputtering targets with Al contents (0.08 at.-% and 0.20 at.-% respectively) were prepared by vacuum induction melting and casting. After hot rolling and annealing, sputtering targets with a length of 3750 mm and a width of 240 mm were obtained.

[0078] Specifically, 370 kg of Ag particles with a purity of 4N were loaded into a graphite crucible along with 7.55 kg or 17.54 kg of small Al blocks with a purity of 4N. First, most of the Ag particles were placed in the crucible, then the Al blocks were placed around the center of the Ag particle pile. Finally, the remaining Ag particles were placed as the top layer. The crucible was slowly heated to a casting temperature of 1040°C. Melting was performed in the degassed vacuum chamber of a conventional vacuum induction furnace (base pressure 1 × 10⁻⁶). -3 mbar to 2×10 -3 This is done in mbar.

[0079] The melt is held for about half an hour to degas and homogenize, and then cast into a cold steel mold to obtain a solid block for subsequent preparation of sputtering targets.

[0080] After preheating the ingot to a temperature range of 500°C to 600°C for approximately 2 hours, it is hot rolled in multiple passes. The rolled sheet is then annealed at a temperature range of 300°C to 350°C for approximately 1 hour.

[0081] Samples were taken from multiple locations on the sputtering target, and the samples were prepared and analyzed according to the above method to determine their uniformity and grain characteristics. Figure 2 A micrograph of an AgAl 0.20 at.-% sputtering target sample is shown.

[0082] Grain characteristics of AgAl sputtering targets As described above, the grain characteristics of the AgAl sputtering target were determined according to DIN EN ISO 643. The results are shown in Table 1 below.

[0083] Table 1: Grain Size Characteristics

[0084] Both sputtering target samples formed fine and uniform grains, with an average grain size of less than 100 μm and a maximum grain size of less than 300 μm.

[0085] Performance of AgAl sputtering targets See Figure 1 The diagram shows a sputtering target, including the sample location.

[0086] As described above, six samples (C1-C6) were measured at different locations on an AgAl 0.20 at.-% sputtering target, with a distance d between these locations being at least 1 / 10 of the target length. In addition, samples were taken at the starting end (B) and the ending end (E) of the target, and another sample (M) was taken from the side at half the length (i.e., the middle of the target length). Samples (B), (E), and (M) were not used to determine the average Al content. The Al content was determined by ICP-OES, and the results are shown in Table 2.

[0087] Table 2: Al content in AgAl 0.20 at.-% sputtering targets

[0088] Based on samples C1 to C6, the average Al content in the AgAl alloy was calculated to be 0.2007 at.-%. The maximum deviation in the samples was 0.0053 at.-% (absolute value), which is 2.7% for C1.

[0089] The oxygen content of the target material was measured to be 3.5 ppm. No oxide inclusions were detected. No arc discharge occurred.

[0090] Example 2 Preparation of AgTi sputtering target AgTi sputtering targets with a titanium content of 0.19 at.-% were prepared by vacuum induction melting and casting, and then hot-rolled to obtain sputtering targets with dimensions comparable to those in Example 1.

[0091] Specifically, 4N purity Ag particles were loaded into a vacuum-calcined clay-graphite crucible. A titanium wire was placed in the center of the crucible, and approximately half of the wire was covered with Ag particles. The apparatus was then slowly heated to a casting temperature of 1040°C. Melting was carried out in a degassed vacuum chamber of a conventional vacuum induction furnace (base pressure 1 × 10⁻⁶). -3 mbar to 2×10 -3 (mbar). During the formation of liquid Ag, the uncovered portion of the titanium wire is continuously absorbed by the melt.

[0092] The melt is left to stand for about half an hour for degassing and homogenization, and then cast into a cold steel mold to form a solid block for subsequent production of sputtering targets.

[0093] After preheating the ingot to a temperature range of 500°C to 600°C for about 2 hours, it undergoes multiple hot rolling processes. The rolled sheet is then annealed at a temperature range of 300°C to 350°C for about 1 hour.

[0094] This method yielded a highly uniform AgTi 0.19at.-% alloy with a sample-to-sample deviation of less than 3%. The oxygen content of the target material was measured to be 3.0 ppm. No oxide inclusions were detected. No arc discharge occurred.

[0095] Example 3 Preparation of AgX alloy layer The preform with dimensions of 488×88×6mm was prepared from a large preform used for full-size targets. 3 The sputtering targets, and the large preforms, were prepared using the method described above. These targets contained AgAl 0.08 at.-% alloy or AgTi 0.19 at.-% alloy and were used to deposit layers on glass. The coating containing the alloy monolayer was deposited on a 2×2×5 cm² substrate using magnetron sputtering in a continuous coating machine. 3 On a glass substrate.

[0096] The other parameters of this method are: Final pressure before treatment: 1×10 -6 mbar Process pressure: 3×10 -3 mbar Argon flow rate: 180 sccm Power density: 1.1 W / cm³ 2 Film deposition in dynamic deposition mode Layers with thicknesses of 10 nm, 20 nm, and 277 nm were prepared. These layers exhibited excellent substrate adhesion and a very smooth and uniform appearance. No increase in micro-arc discharge was observed compared to pure Ag target material.

Claims

1. A sputtering target comprising an AgX alloy, the AgX alloy being composed of Ag and 0.06 at.-% to 0.50 at.-% X, wherein, X is at least one alloying element, which is selected from the group consisting of Mg, Al, Si, Ca, Sr, Sc, Y, rare earth metals, Ti and Ge, and combinations thereof; wherein the oxygen content of the AgX alloy is less than 50 ppm-wt.

2. The sputtering target according to claim 1, wherein, The at least one alloying element X is Al.

3. The sputtering target according to claim 1, wherein, The at least one alloying element X is Ti.

4. The sputtering target according to claim 1, wherein, The rare earth metals are La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, preferably La and / or Ce.

5. The sputtering target according to any one of the preceding claims, wherein, The AgX alloy is composed of Ag and at least one alloying element X in the range of 0.07 at.-% to 0.30 at.-% and preferably Ag and at least one alloying element X in the range of 0.08 at.-% to 0.20 at.-% 6. The sputtering target according to any one of the preceding claims, wherein, The AgX alloy has an average grain size in the range of 10 μm to less than 150 μm, and / or the AgX alloy has a maximum grain size of less than 300 μm.

7. The sputtering target according to any one of the preceding claims, wherein, The oxygen content of the AgX alloy is less than 20 ppm-wt., preferably less than 10 ppm-wt., and more preferably less than 5 ppm-wt.

8. The sputtering target according to any one of the preceding claims, wherein, The AgX alloy has a metal purity of at least 99.9 wt.-% (3N), preferably at least 99.95 wt.-% (3N5).

9. The sputtering target according to any one of the preceding claims, wherein, The content of X measured at any location on the sputtering target deviates from the average content of X in the sputtering target by no more than 20%, preferably no more than 10%, and the content and average content of X are determined by ICP-OES as described in the specification.

10. The sputtering target according to any one of the preceding claims, wherein, Measurements were taken in five regions at any location on the scanning electron microscope (SEM) sample, as described in the instructions, including measurements at 1 mm. 2 The clusters of oxide form detected in the region were larger than 1 µm. 2 The number of inclusion clusters of alloying element X does not exceed two.

11. A method for preparing a sputtering target according to any one of the preceding claims, comprising preparing the AgX alloy by heating an Ag metal block to a temperature range of 980°C to 1200°C in an inert container under vacuum or inert gas conditions and in the presence of at least one alloying element X.

12. The method according to claim 11, wherein, The at least one alloying element X is in the form of a solid material block with a specified size, preferably in the form of a wire with a specified diameter and a specified length. The at least one alloying element X is at least partially placed in the volume of the Ag metal block. The Ag metal block and the at least one alloying element X are heated to prepare an Ag melt. The at least one alloying element X is dispersed in the Ag melt.

13. The method according to claim 11, wherein, The at least one alloying element X is in block form. The Ag metal blocks and the at least one alloying element X are prepared in a stacked form, wherein the stack 2 of the at least one alloying element X is placed on top of the stack 1 of the Ag metal blocks and is covered by the stack 3 of the remaining Ag metal blocks. The Ag metal blocks and the at least one alloying element X are heated to prepare Ag melt, wherein the at least one alloying element X is dispersed in the Ag melt.

14. A sputtering target prepared by any one of claims 11 to 13.

15. A layer formed by sputtering an AgX alloy from a sputtering target according to any one of claims 1 to 10 or 14 onto a substrate.

Images