TWI856716B - Composite target and method of preparing the same - Google Patents

Abstract

Provided are a composite target and a method of making the same. The composite target includes a supporting plate and a Ruthenium (Ru)-containing sputtering target bonded to the supporting plate. The supporting plate includes a first component which can be subjected to a solid solution with Ru and has a thermal conductivity larger than 50 W/m‧K. Based on a total atom number of the supporting plate, a content of the first component is from 70 at% to 100 at%. The Ru-containing sputtering target includes an oxide component; based on a total atom number of the Ru-containing sputtering target, a content of the oxide component is from 20 at% to 42 at%. The ratio of the bending strength of the Ru-containing sputtering target to that of the supporting plate is from 0.1 to 0.8. The ratio of the coefficient of linear thermal expansion of the Ru-containing sputtering target to that of the supporting plate is from 0.8 to 1.2. By simultaneously controlling the above-mentioned technical features, the sputtering target assembly of the present invention can omit the Indium welding process and further improve the bonding ability between the Ru-containing sputtering target and the supporting plate.

Description

Composite target material and its manufacturing method

This invention relates to a composite target material, in particular to a composite target material suitable for preparing a perpendicular magnetic recording media; in addition, this invention also relates to a method for manufacturing the composite target material.

Magnetic recording refers to the use of the hysteresis properties of magnetic materials to store information in recording media. With the consumer demand for portable recording media, the rise of big data, and the generation of massive amounts of information, users are increasingly eager to increase the information storage density of magnetic recording media based on the ability of the aforementioned recording media to record stably. Therefore, how to improve the recording density of magnetic recording media has always been a research focus in related fields.

Generally speaking, the layered structure of a perpendicular magnetic recording medium includes a substrate, an adhesion layer, a soft underlayer, a seed layer, an intermediate layer, a magnetic recording layer, a lubricating layer, and a cover layer from bottom to top. The industry believes that controlling the crystal properties of the magnetic recording layer can further improve the recording density of perpendicular magnetic recording media. Therefore, the industry has recently tried to add a base layer under the magnetic recording layer. The base layer can allow the magnetic recording layer to have better stacking growth, and assist the magnetic recording layer to obtain uniformly distributed grains, adjust its segregation structure, crystal orientation and other properties.

The aforementioned base layer is often formed by sputtering a target material having a certain content of oxide components. However, the existing target material having a certain content of oxide components has problems such as poor heat dissipation and low strength, which causes the aforementioned target material to be prone to cracking and deformation during use, affecting the practicality of subsequent applications in the sputtering process and the quality of the coating obtained by sputtering. At present, in order to improve the strength of the aforementioned target material, it is usually necessary to weld the aforementioned target material with a supporting target material to form a target material assembly to improve the overall strength of the target material assembly, but the target material in the aforementioned target material assembly often has low bonding properties with the supporting target material.

In view of the defects faced by the prior art, the purpose of this invention is to provide a composite target material that can bond a target material containing an oxide component to a supporting target material without using a welding method, and the bonding between the target material containing an oxide component and the supporting target material is improved, thereby reducing or even avoiding the phenomenon of warping of the target material containing an oxide component when the composite target material is subsequently used in a sputtering process.

Another purpose of this invention is to provide a composite target material, which contains an oxide component having good flatness after sputtering.

Another purpose of this invention is to provide a composite target material, the flexural strength of which is greater than the flexural strength of the target material itself, so that the cracking phenomenon of the target material containing oxide components during subsequent sputtering can be reduced or even avoided.

To achieve the above-mentioned purpose, the present invention provides a composite target material, which includes: a support target material; and a ruthenium (Ru) target material, the ruthenium target material being bonded to the support target material. The support target material includes a first component capable of solid solution with ruthenium, and the thermal conductivity of the first component is greater than 50 W/m.K; based on the total number of atoms of the support target material as a whole, the total content of the first component is 70 atomic percentage (atomic percentage, at%) to 100 at%; the ruthenium target material includes ruthenium and an oxide component; based on the total number of atoms of the ruthenium target material as a whole, the total content of the oxide component is 20 at% to 42 at%. The ratio of the bending strength of the ruthenium-containing target to the supporting target is 0.1 to 0.8; the ratio of the coefficient of linear thermal expansion (CTE or CLTE, α) of the ruthenium-containing target to the supporting target is 0.8 to 1.2.

By controlling the composite target of the invention, the following technical features are simultaneously possessed: (I) the supporting target contains the first component capable of solid solution with ruthenium, and the thermal conductivity of the first component is greater than 50 W/m.K; (II) the total content of the first component in the supporting target is 70 at% to 100 at%, (III) the total content of the oxide component in the ruthenium-containing target is 20 at% to 42 at%, (IV) the ratio of the flexural strength of the ruthenium-containing target to that of the supporting target is 0.1 to 0.8; (V) the ratio of the CTE of the ruthenium-containing target to that of the supporting target is 0. .8 to 1.2, so the ruthenium-containing target and the supporting target no longer need to be joined by welding, which not only reduces the process steps but also avoids the problem of solder overflow due to temperature increase during the subsequent sputtering process, thereby reducing the risk of contaminating the coating. In addition, the supporting target and the ruthenium-containing target have good bonding strength (for example, greater than 120 kilograms of force per square centimeter (kgf/ ^cm2 )), and can obtain a higher flexural strength than the ruthenium-containing target itself, thereby reducing or even avoiding the occurrence of warping, deformation, cracks, etc. of the ruthenium-containing target during subsequent sputtering. Moreover, after the sputtering is completed, the ruthenium-containing target can still maintain good flatness.

According to this invention, the first component that can form a solid solution with ruthenium means that the solid solubility of the first component in ruthenium metal is greater than 5 mole%. The aforementioned solid solubility refers to the maximum content of the solute in the solid solution at 1000°C; the solid solution refers to the alloy phase in which the solute atoms (such as the first component) are dissolved in the solvent (such as ruthenium metal) lattice and still maintain the solvent type.

Preferably, the thermal conductivity of the first component is above 70W/m.K, but not limited thereto.

Preferably, the first component comprises cobalt (Cobalt, Co), iron (Iron, Fe), chromium (Chromium, Cr), molybdenum (Molybdenum, Mo), nickel (Nickel, Ni) or a combination thereof.

In some embodiments, the support target further comprises a second component; the second component comprises aluminum (Aluminum, Al), zinc (Zinc, Zn), tin (Tin, Sn), copper (Copper, Cu), palladium (Palladium, Pd), tungsten (Tungsten, W), silicon (Silicon, Si), niobium (Niobium, Nb), magnesium (Magnesium, Mg) or a combination thereof.

Preferably, based on the total number of atoms of the supporting target material as a whole, the total content of the second component is greater than 0at% and less than or equal to 30at%, but not limited thereto. According to this invention, when there is only one option for the aforementioned second component, the "total content of the second component" is the content of the single second component; when the aforementioned second component includes more than two options, the "total content of the second component" is the sum of the individual contents of these second components; for example, when the second component is a combination of 5at% copper and 3at% tin, the total content of the second component is 8at%.

Preferably, the flexural strength of the supporting target material is greater than 700 MPa, but not limited thereto. More preferably, the flexural strength of the supporting target material is 760 MPa to 1550 MPa.

In some embodiments, the oxide component contained in the ruthenium-containing target is selected from the group consisting of aluminum oxide, titanium oxide, silicon oxide, boron oxide, cobalt oxide, chromium oxide, magnesium oxide, niobium oxide, tungsten oxide, manganese oxide, zirconium oxide, and combinations thereof. Specifically, aluminum oxide may be aluminum trioxide (Al ₂ O ₃ ); titanium oxide may be titanium dioxide (TiO ₂ ); silicon oxide may be silicon dioxide (SiO ₂ ); boron oxide may be boron trioxide (B ₂ O ₃ ); cobalt oxide may be cobalt monoxide (CoO), cobalt tetraoxide (Co ₃ O ₄ ), etc.; chromium oxide may be chromium trioxide (Cr ₂ O ₃ ), etc.; magnesium oxide may be magnesium monoxide (MgO); niobium oxide may be niobium pentoxide (Nb ₂ O ₅ ), etc.; tantalum oxide may be tantalum pentoxide (Ta ₂ O ₅ ); yttrium oxide may be yttrium trioxide (Y ₂ O ₃ ); tungsten oxide may be tungsten trioxide (WO ₃ ); manganese oxide may be manganese monoxide (MnO), manganese dioxide (MnO ₂ ), manganese trioxide (Mn ₂ O ₃ ), etc.; zirconium oxide may be zirconium dioxide (ZrO ₂ ).

According to this invention, when there is only one option for the aforementioned oxide component, the "total content of the oxide component" is the content of the single oxide; when the aforementioned oxide component includes two or more options, the "total content of the oxide component" is the sum of the individual contents of these oxides; for example, when the oxide component is a combination of 28at% chromium oxide and 5at% manganese oxide, the total content of the oxide component is 33at%. Preferably, based on the total number of atoms of the entire ruthenium-containing target, the total content of the oxide component is 20at% to 39at%, but is not limited thereto.

In some embodiments, the ruthenium-containing target further comprises an additive component; the additive component comprises platinum (Pt), cobalt, chromium, boron (B), titanium (Ti), rhenium (Re), aluminum or a combination thereof.

Preferably, based on the total number of atoms in the ruthenium-containing target material, the total content of the added component is greater than or equal to 18at% and less than or equal to 47at%.

Preferably, based on the total number of atoms in the ruthenium-containing target material, the total ruthenium content is 15at% to 62at%, but not limited thereto.

In some embodiments, the ratio of the flexural strength of the ruthenium-containing target to the supporting target is 0.1 to 0.65, but not limited thereto. In other embodiments, the ratio of the flexural strength of the ruthenium-containing target to the supporting target is 0.25 to 0.8, but not limited thereto. The flexural strength is measured by a four-point bending test.

In some embodiments, the flexural strength of the ruthenium-containing target is 152 MPa to 700 MPa, but is not limited thereto.

In some embodiments, the flexural strength of the supporting target material is 710MPa to 1550MPa, but is not limited thereto.

Preferably, the ratio of the linear expansion coefficient of the ruthenium-containing target to the supporting target is 0.88 to 1.14, but not limited thereto. The linear expansion coefficient is measured using the standard method ASTM E831.

In some embodiments, the linear expansion coefficient of the ruthenium-containing target is 5.0*10 ^-6 /°C to 12.3*10 ^-6 /°C, but is not limited thereto.

In some embodiments, the linear expansion coefficient of the support target is 4.9*10 ^-6 /°C to 12.0*10 ^-6 /°C, but is not limited thereto.

In addition, the invention also provides a method for preparing a composite target, which includes: combining a supporting target with a ruthenium-containing target to obtain the composite target; wherein the supporting target includes a first component that can be solid-dissolved with ruthenium, and the thermal conductivity of the first component is greater than 50W/m.K; based on the total number of atoms of the supporting target as a whole, the total content of the first component is 70at% to 100at%; the ruthenium-containing target includes ruthenium and an oxide component; based on the total number of atoms of the ruthenium-containing target as a whole, the total content of the oxide component is 20at% to 42at%. wherein the ratio of the flexural strength of the ruthenium-containing target to the supporting target is 0.1 to 0.8; and the ratio of the linear expansion coefficient of the ruthenium-containing target to the supporting target is 0.8 to 1.2.

This invention limits the supporting target material to contain a large amount of specific components that have good thermal conductivity and can be solid-dissolved with ruthenium, so that it can be more firmly bonded to the ruthenium-containing target material. By limiting the content range of the specific components of the supporting target material, as well as limiting the ratio relationship between the flexural strength and the ratio relationship between the ruthenium-containing target material and the supporting target material, it helps to improve the mechanical strength between the ruthenium-containing target material and the supporting target material. Therefore, the invention can directly bond the ruthenium-containing target and the supporting target to form the composite target, thereby omitting the welding process, and the bonding strength between the ruthenium-containing target and the supporting target is good, so when the composite target is used for subsequent sputter plating, the problem of solder overflow caused by temperature rise can be avoided, and the warping, deformation, cracking, etc. of the ruthenium-containing target can be reduced or even avoided; in addition, after sputter plating, the ruthenium-containing target can also maintain good flatness.

According to this invention, the supporting target material can be prepared using known raw materials, or it can be a residual target after use, but it is not limited to this.

In some embodiments, the support target material can be made by molding a base material containing a first component raw material. Preferably, the molding method includes a sintering method, but is not limited thereto.

According to the present invention, the sintering method can be hot pressing (HP), hot isostatic pressing (HIP) or spark plasma sintering (SPS), or two or more of the sintering methods can be combined for sintering. Preferably, the sintering temperature of the sintering process can be greater than or equal to 700°C and less than or equal to 1200°C, and the sintering pressure can be greater than or equal to 220 bar and less than or equal to 1300 bar. For example, when HP is used for sintering, the sintering temperature may be 800°C to 1200°C, the sintering pressure may be 350 bar to 400 bar, and the sintering time may be 1 hour to 3 hours, but not limited thereto; when SPS is used for sintering, the sintering temperature may be 700°C to 1100°C, the sintering pressure may be 900 bar to 1300 bar, and the sintering time may be 5 minutes to 1 hour, but not limited thereto.

Specifically, the first raw material includes cobalt raw material, iron raw material, chromium raw material, molybdenum raw material, nickel raw material or a combination thereof. Preferably, the purity of each component in the first raw material is above 99.9%.

In some embodiments, the base material for preparing the support target may further include a second component raw material, that is, the base material includes the first component raw material and the second component raw material. When the base material includes the second component raw material, the support target finally prepared includes the second component. The second component raw material includes aluminum raw material, zinc raw material, tin raw material, copper raw material, palladium raw material, tungsten raw material, silicon raw material, niobium raw material, magnesium raw material or a combination thereof. Preferably, the purity of each component in the second component raw material is above 99.9%.

In some embodiments, the base material for preparing the supporting target can be mixed with various raw materials in the base material by rolling, grinding, etc.

According to this invention, the ruthenium-containing target can be formed by sintering the raw material mixture.

Specifically, the raw material mixture for preparing the ruthenium-containing target material contains at least ruthenium raw material and oxide component raw material, but is not limited thereto.

According to the present invention, the ruthenium raw material may be ruthenium metal with a purity of 99.95% or more, ruthenium alloy with a ruthenium content of 50 weight percent (wt%) or more, or a combination thereof, but is not limited thereto. More preferably, the ruthenium raw material may be ruthenium metal with a purity of 99.95% or more. Preferably, the average particle size of the ruthenium raw material is 35 micrometers (μm) to 80μm.

According to the invention, the oxide component raw material can be selected from the group consisting of aluminum oxide raw materials, titanium oxide raw materials, silicon oxide raw materials, boron oxide raw materials, cobalt oxide raw materials, chromium oxide raw materials, magnesium oxide raw materials, niobium oxide raw materials, tantalum oxide raw materials, yttrium oxide raw materials, tungsten oxide raw materials, manganese oxide raw materials, zirconium oxide raw materials and combinations thereof. Preferably, the purity of each component in the oxide component raw materials is above 99.9%.

In some embodiments, the raw material mixture for preparing the ruthenium-containing target may further include an additive raw material, that is, the raw material mixture includes the ruthenium raw material, the oxide raw material and the additive raw material. When the raw material mixture includes the additive raw material, the final ruthenium-containing target includes the additive. The additive raw material includes platinum raw material, cobalt raw material, chromium raw material, boron raw material, titanium raw material, rhodium raw material, aluminum raw material or a combination thereof. Preferably, the purity of each component in the additive raw material is above 99.9%.

According to the invention, the raw material mixture can be mixed uniformly by any mixing method. For example, the mixing method can use a high-speed grinder to perform the grinding process, but it is not limited to this. Preferably, the grinding time of the grinding process is 1 hour to 4 hours, but it is not limited to this.

In some embodiments, the raw material mixture may further include a pre-pressing step before the sintering process; that is, the raw material mixture may be subjected to the pre-pressing step after the grinding process, and the pre-pressing step may be any means capable of pressing the raw material mixture into a fixed shape. For example, the pre-pressing step may be placing the raw material mixture in a hydraulic press and performing the pre-pressing step at a pressure of about 15 bar to 110 bar, but is not limited thereto. Preferably, the pressure of the pre-pressing step is 20 bar to 105 bar.

According to the invention, the sintering process can be performed by hot pressing, hot isostatic pressing or plasma sintering alone, or by combining two or more of the above sintering methods. Preferably, the sintering temperature of the sintering process can be greater than or equal to 650°C and less than or equal to 1250°C, and the sintering pressure can be greater than or equal to 220 bar and less than or equal to 1300 bar. For example, when HP is used for sintering, the sintering temperature can be 800℃ to 1200℃, the sintering pressure can be 350bar to 400bar, and the sintering time can be 1 hour to 4 hours, but not limited thereto; when SPS is used for sintering, the sintering temperature can be 700℃ to 1150℃, the sintering pressure can be 900bar to 1300bar, and the sintering time can be 5 minutes to 1.5 hours, but not limited thereto.

In some embodiments, the method of bonding the support target material to the ruthenium-containing target material includes: placing the raw material mixture for preparing the ruthenium-containing target material directly on the support target material, and then performing the sintering process.

In other embodiments, the method of bonding the support target material to the ruthenium-containing target material includes: firstly forming the ruthenium-containing target material from a raw material mixture (i.e. the aforementioned raw material mixture) through a sintering process (i.e. the aforementioned sintering process); and then placing the ruthenium-containing target material on the support target material for a sintering bonding process.

Specifically, the sintering and bonding process can refer to the sintering method, sintering time, sintering temperature, sintering pressure and other parameters of the above sintering process. The sintering process performed first and the sintering and bonding process performed later can be the same or different.

Preferably, before the sintering and bonding process, the ruthenium-containing target and the supporting target can be subjected to a surface black skin removal process and/or a cleaning process, but not limited thereto.

In some embodiments, the structure of the support target can be a flat plate structure parallel to the ruthenium-containing target, or a concave-convex structure embedded in the ruthenium-containing target, but is not limited thereto. For example, the vertical cross-section of the support target can be concave or saw-toothed, and the ruthenium-containing target is filled therein.

In this specification, the range represented by "a small number to a large number" means that the range is greater than or equal to the small number and less than or equal to the large number unless otherwise specified. For example: the total content of the first component is 70 atomic percent to 100 atomic percent, which means that the total content of the first component ranges from "greater than or equal to 70 atomic percent and less than or equal to 100 atomic percent".

10: Test piece

11: Supporting target

12: Ruthenium-containing target

Figure 1 is a schematic diagram of the composite target specimen used in Analysis 3.

In order to verify the influence of the raw material composition of the ruthenium-containing target, the raw material composition of the supporting target, the ratio of the flexural strength of the ruthenium-containing target and the supporting target, and the ratio of the linear expansion coefficient of the ruthenium-containing target and the supporting target on the composite target, several composite targets are listed below as examples to explain in detail the implementation of this creation. Those with ordinary knowledge in the relevant technical field can easily understand the advantages and effects that can be achieved by this creation through the content of this manual, and make various modifications and changes without deviating from the spirit of this creation to implement or apply the content of this creation.

Preparation Examples B1 to B38: Supporting Targets

First, according to the composition of the supporting target material listed in Table 2, each group weighs an appropriate amount of the first component raw material powder with an average particle size of 5μm to 200μm and/or the second component raw material powder with an average particle size of 5μm to 200μm in sequence and mixes them in a mixing device by rolling to obtain a base material. Among them, the first component is selected from the group consisting of cobalt, iron, chromium, molybdenum, nickel and their combination, and the thermal conductivity of each selection is listed in Table 1.

Next, the base material is placed in a mold and subjected to a sintering molding process to obtain the support target materials of Preparation Examples B1 to B38. If HP is used for sintering, the sintering pressure is about 380 bar, the sintering temperature is about 800°C to 1200°C, and the sintering time is 1 hour to 3 hours; if SPS is used for sintering, the sintering pressure is about 1188 bar, the sintering temperature is about 700°C to 1100°C, and the sintering time is 5 minutes to 1 hour.

In Table 2, the composition of the support target materials of Preparation Example B1 to Preparation Example B38 can be represented by the general formula aY-bZ; wherein a represents the content ratio of the number of atoms of the first component relative to the total number of atoms of the support target material, Y represents the first component, which can be selected from the group consisting of cobalt, iron, chromium, molybdenum, nickel and combinations thereof; b represents the content ratio of the number of atoms of the second component relative to the total number of atoms of the support target material, and Z represents the second component, which is selected from the group consisting of aluminum, zinc, tin, copper, palladium, tungsten, silicon, niobium, magnesium and combinations thereof.

Preparation Examples T1 to T10, Preparation Examples T24 to T26: Ruthenium-containing targets

First, according to the composition of the ruthenium-containing target listed in Table 2, weigh appropriate amounts of ruthenium metal powder with an average particle size of 40μm, oxide component raw material powder with an average particle size of 0.1μm to 5μm, and/or additive component raw material powder with an average particle size of 1μm to 40μm, and mix them in a high-speed grinder, and then grind them for 1 hour to 4 hours to obtain a raw material mixture.

Next, the raw material mixture is filled into a mold and pre-pressed at a pressure of about 103 bar; then, the pre-pressed raw material mixture is subjected to a sintering process, and a circular target with a diameter of 165 millimeters (mm) and a thickness of 5 mm is obtained after processing, that is, the ruthenium-containing targets of Preparation Examples T1 to T10 and Preparation Examples T24 to T26 are obtained. Among them, if HP is used for sintering, the sintering pressure is about 380bar, the sintering temperature is about 800℃ to 1200℃, and the sintering time is 1 hour to 3 hours; if SPS is used for sintering, the sintering pressure is about 1188bar, the sintering temperature is about 700℃ to 1100℃, and the sintering time is 5 minutes to 1 hour.

Examples 1 to 10: Composite target

First, a grinder was used to remove the black skin on the surfaces of the support targets of Preparation Examples B1 to B10 and the ruthenium-containing targets of Preparation Examples T1 to T10 to be bonded. Then, according to Table 2, the support targets of each group of Preparation Examples and the ruthenium-containing targets of Preparation Examples were stacked to form a stacked structure.

Then, the stacked structures of each group are subjected to a sintering bonding process to obtain the composite target materials of Examples 1 to 10. If HP is used for sintering bonding, the sintering pressure is about 380 bar, the sintering temperature is about 800°C to 1200°C, and the sintering time is 1 hour to 3 hours; if SPS is used for sintering bonding, the sintering pressure is about 1188 bar, the sintering temperature is about 700°C to 1100°C, and the sintering time is 5 minutes to 1 hour.

Comparative Examples 1 to 3: Target Assembly

First, the support targets of Preparation Examples B24 to B26 and the ruthenium-containing targets of Preparation Examples T24 to T26 were processed according to the drawings using wire cutting and lathe. Then, according to Table 2, the support targets and ruthenium-containing targets of Comparative Examples 1 to 3 were welded to obtain target assemblies of Comparative Examples 1 to 3. The welding parameters are as follows: 1. Heating temperature: 200°C; 2. Solder: indium solder; 3. Welding rate: greater than 98%.

Preparation Examples T11 to T23, Preparation Examples T27 to T38: Raw material mixture containing ruthenium target

According to the composition of the ruthenium-containing target listed in Table 2, weigh appropriate amounts of ruthenium metal powder with an average particle size of 40μm, oxide component raw material powder with an average particle size of 0.1μm to 5μm, and/or additive component raw material powder with an average particle size of 1μm to 40μm, and mix them in a high-speed grinder, and then grind them for 1 hour to 4 hours to obtain the raw material mixtures of Preparation Examples T11 to T23 and Preparation Examples T27 to T38.

Examples 11 to 23, Comparative Examples 4 to 15: Composite targets

First, prepare the supporting targets of each set of embodiments and comparative examples (i.e., the supporting targets of Preparation Examples B11 to B23, Preparation Examples B27 to B38) according to Table 2, and place the supporting targets of each set under the mold, and then fill in the raw material mixtures of Preparation Examples T11 to T23, Preparation Examples T27 to T38 in sequence according to Table 2.

Subsequently, pre-pressing is performed at a pressure of about 103 bar; after the pre-pressing step is completed, the pre-pressed raw material mixture is subjected to a sintering process to obtain the composite target materials of Examples 11 to 23 and Comparative Examples 4 to 15. If HP is used for sintering, the sintering pressure is about 380 bar, the sintering temperature is about 800°C to 1200°C, and the sintering time is 1 hour to 3 hours; if SPS is used for sintering, the sintering pressure is about 1188 bar, the sintering temperature is about 700°C to 1100°C, and the sintering time is 5 minutes to 1 hour.

In Table 2, in the composite targets of Examples 1 to 23, the target assemblies of Comparative Examples 1 to 3, and the composite targets of Comparative Examples 4 to 15, the composition of the ruthenium-containing target can be represented by the general formula of cRu-dX-e(OE); wherein c represents the content ratio of the number of atoms of Ru relative to the total number of atoms of the ruthenium-containing target; d represents the content ratio of the number of atoms of the additive component relative to the total number of atoms of the ruthenium-containing target; X represents the additive component, which is selected from the group consisting of platinum, cobalt, chromium, boron, titanium, ruthenium, aluminum, and combinations thereof; e represents the content ratio of the number of atoms of the oxide component relative to the total number of atoms of the ruthenium-containing target; OE represents the oxide component, which is selected from the group consisting of Al ₂ O ₃ , TiO ₂ , SiO ₂ , B ₂ O ₃ , CoO, Co ₃ O ₄ , Cr ₂ O ₃ , MgO, Nb ₂ O ₅ , Ta ₂ O ₅ , Y ₂ O ₃ , WO ₃ , MnO ₂ , ZrO ₂ and combinations thereof. When the oxide component is alumina, for example, e represents the content ratio of the sum of the number of oxygen atoms and the number of aluminum atoms relative to the total number of atoms in the ruthenium-containing target.

Analysis 1: Flexural strength

First, the scraps of the support target materials of Preparation Examples B1 to B38 were processed by wire cutting and lathe into test pieces of support target materials with dimensions of 3mm thickness, 4mm width and 50mm length.

Secondly, the scraps of the ruthenium-containing targets of Preparation Examples T1 to T10, Preparation Examples T24 to T26, and the scraps of the ruthenium-containing targets in the composite targets of Examples 11 to 23 and Comparative Examples 4 to 15 were processed by wire cutting and lathe into test pieces of ruthenium-containing targets with a thickness of 3 mm, a width of 4 mm, and a length of 50 mm.

In addition, the composite targets of Examples 1 to 23, the target assemblies of Comparative Examples 1 to 3, and the composite targets of Comparative Examples 4 to 15 were processed by wire cutting and lathe into composite target specimens with dimensions of 3 mm in thickness, 4 mm in width, and 50 mm in length.

The above-mentioned target support specimens, target containing ruthenium specimens, and composite target specimens were placed on a universal testing machine (model: Instron 3365) to perform a four-point bending test. The specific steps are to place each test piece on a four-point bending jig, and measure the maximum load before the test piece is bent to fracture under the operating conditions of a pressurizing speed of 0.5 mm/min and a span of 40 mm, and then calculate according to the following formula: Flexural strength = (3×maximum load×span)/(2×test piece width×test piece thickness×test piece thickness), to obtain the flexural strength of the composite targets of Examples 1 to 23, the target material assemblies of Comparative Examples 1 to 3, and the composite targets of Comparative Examples 4 to 15, as well as the flexural strength of the ruthenium-containing targets and supporting targets contained therein, and the results are listed in Table 3. In addition, the ratio of the flexural strength of the ruthenium-containing target and the flexural strength of the supporting target of each group is calculated and recorded in Table 3.

Analysis 2: Linear expansion coefficient

First, prepare the composite target samples of Examples 1 to 23 and Comparative Examples 1 to 15, as well as the ruthenium-containing target sample and the supporting target sample contained in the composite target of each Example and Comparative Example in the same manner as the sample preparation in Analysis 1; the difference between the samples of Analysis 2 and Analysis 1 is only in the size, and the size of each sample of Analysis 2 is 5 mm thick, 5 mm wide, and 20 mm long.

The above-mentioned test pieces were placed in a dilatometer (brand: NETZSCH, model: DIL 402) to analyze the linear expansion coefficient of each test piece, and the results were recorded in Table 3. In addition, the ratio of the linear expansion coefficient of each set of ruthenium-containing target material to the linear expansion coefficient of the supporting target material was calculated and recorded in Table 3. The relevant test conditions are as follows: 1. Vacuum degree: 10 ^-3 to 10 ^-4 mbar; 2. Atmosphere type: Argon (Ar); 3. Test temperature range: room temperature to 1200°C.

Analysis 3: Shear stress on the joint surface

First, the composite targets of Examples 1 to 23, the target assemblies of Comparative Examples 1 to 3, and the composite targets of Comparative Examples 4 to 15 were respectively processed by wire cutting and lathe to obtain the test pieces 10 shown in FIG. 1 , that is, in each set of test pieces 10, the support target 11 and the ruthenium-containing target 12 were staggered and overlapped in the length direction; wherein the support target 11 had a thickness of 1 cm, a width of 2.5 cm, and a length of 7.5 cm; the ruthenium-containing target 12 had a thickness of 1 cm, a width of 2.5 cm, and a length of 5.5 cm; the contact length of the two in the length direction was 4 cm, and the contact area of the two was 10 cm ² (4 cm x 2.5 cm).

The above-mentioned test pieces 10 were placed on a tensile fixture of a universal testing machine (model: Instron 3365) to perform a tensile strength test, and the maximum shear force before the joint surface of the support target 11 and the ruthenium-containing target 12 in each test piece 10 was measured and converted into shear stress per unit area. The results are listed in Table 3. If the measured joint surface shear stress is greater than 120kgf/ ^cm2 , it is rated as "passed", otherwise, if the measured joint surface shear stress is less than or equal to 120kgf/ ^cm2 , it is rated as "failed".

Analysis 4: Flatness of ruthenium-containing target

First, a sputtering process was performed using the composite targets of Examples 1 to 23, the target assemblies of Comparative Examples 1 to 3, and the composite targets of Comparative Examples 4 to 15 (round targets with a diameter of 165 mm and a thickness of 5 mm). The relevant parameters of the sputtering process are as follows: 1. Machine: magnetron sputtering machine; 2. Vacuum: 10 ^-2 torr to 10 ^-3 torr; 3. Power: 3000 watts; 4. Sputtering time: 1800 seconds; 5. Chiller temperature: 25°C.

Next, each set of sputtered specimens was placed on a marble platform of a three-dimensional coordinate measuring instrument (model: Brown & Sharpe Global Performance), and the height of five sampling positions on the outer surface of the ruthenium-containing target of each set of specimens was measured; wherein the five sampling positions are the center point of the ruthenium-containing target in each set, and the four sides of the ruthenium-containing target (i.e., the four positions above, below, left, and right of the center point and 30 mm away from the edge of the ruthenium-containing target). The three-dimensional coordinate measuring instrument calculated the "flatness" of the heights measured at these five sampling positions using the least square method, and recorded the flatness of each set of composite targets in Table 3. If the measured flatness is less than 0.3mm, it is rated as "good", whereas if the measured flatness is equal to or greater than 0.3mm, it is rated as "poor".

Discussion of experimental results

According to the preparation methods of each embodiment and the experimental results in Table 3, it can be seen that when the composite target material has at least the following technical characteristics simultaneously: (I) the first component contained in the supporting target material has the ability to form a solid solution with ruthenium, and the thermal conductivity of the first component is greater than 50W/m. K, (II) the total content of the first component in the supporting target is 70at% to 100at%, (III) the total content of the oxide component in the ruthenium-containing target is 20at% to 42at%, (IV) the ratio of the flexural strength of the ruthenium-containing target to the supporting target is 0.1 to 0.8, (V) the ratio of the CTE of the ruthenium-containing target to the supporting target is 0.8 to 1.2, the ruthenium-containing target and the supporting target no longer need to be welded through a solder, and can have a good bonding strength with a bonding surface shear stress greater than 120kgf/ ^cm2 . This proves that the technical means of the present invention can indeed effectively improve the bonding between the ruthenium-containing target and the supporting target. In addition, the composite targets of each embodiment have a higher flexural strength than the ruthenium-containing target itself, so the warping, deformation and cracking of the ruthenium-containing target can be reduced or even avoided during the subsequent sputtering. Furthermore, after the sputtering is completed, the target surface of the ruthenium-containing target can still maintain good flatness. In contrast, the composite targets of Comparative Examples 4 to 15 do not simultaneously possess the aforementioned technical means (I) to (V), so the composite targets of each comparative example cannot simultaneously have good bonding strength and maintain good flatness of the target surface after the sputtering is completed.

Further referring to the combination of Example 1 and Comparative Example 1 and Comparative Example 4, although the ruthenium-containing target material contained in the composite target material of Example 1 and the target material assembly of Comparative Example 1 and the composite target material of Comparative Example 4 has the same main component, which is 40Ru-25Co-25TiO ₂ -10SiO ₂ However, the components of the supporting targets of Comparative Examples 1 and 4 are completely made of Cu which cannot be dissolved in Ru, and the linear expansion coefficient thereof is too high, so that the ratio of the linear expansion coefficients of the ruthenium-containing target and the supporting target is less than 0.8 (i.e., 0.43). Therefore, whether they are joined by welding or sintering, the shear stress of the joint surface between the ruthenium-containing target and the supporting target of the target assembly of Comparative Example 1 and the composite target of Comparative Example 4 is significantly smaller than that of the composite target of Example 1. Moreover, after sputtering, the target surface of the ruthenium-containing target of the target assembly of Comparative Example 1 and the composite target of Comparative Example 4 cannot have good flatness.

Similarly, the composite targets of Comparative Examples 5 to 8 have the same main component as the ruthenium-containing target contained in the composite target of Example 1, which is expressed as 40Ru-25Co-25TiO ₂ -10SiO ₂ . However, since the supporting targets contained in Comparative Examples 5 to 8 do not contain at least 70 at % of the first component, the composite targets of Comparative Examples 5 to 8 cannot have the advantages of high joint shear stress and good flatness of the target surface after sputtering of the ruthenium-containing target.

Looking at the composite targets of Comparative Examples 13 and 14, each of them has the same main component as the ruthenium-containing target contained in the composite target of Example 1, and the contained support target also contains more than 70at% of the first component; however, since the composite targets of Comparative Examples 13 and 14 do not control the ratio of the linear expansion coefficients of the ruthenium-containing target and the support target, although it can make the ruthenium-containing target and the support target have good joint surface shear stress, when the composite target is used in the sputtering process, the target surface of the ruthenium-containing target contained therein obviously cannot have good flatness.

Looking at the composite target of Comparative Example 15, although the ruthenium-containing target and the supporting target contained therein have appropriate components with appropriate contents, the composite target of Comparative Example 15 does not control the ratio of the flexural strength of the ruthenium-containing target to the supporting target, and the flexural strength of the supporting target is less than 700MPa and less than the flexural strength of the ruthenium-containing target. Therefore, the flexural strength of the composite target of Comparative Example 15 is less than the flexural strength of the ruthenium-containing target contained therein. Under the above circumstances, the technical personnel in this field will not consider using the composite target.

In summary, the invention can achieve the improvement of the bonding between the ruthenium-containing target and the supporting target by properly controlling the content of the first component of the supporting target, the content of the oxide component of the ruthenium-containing target, and the ratio of the CTE and the flexural strength between the ruthenium-containing target and the supporting target. Moreover, after being applied to the sputtering process, the ruthenium-containing target contained therein can still have the advantage of good flatness. Accordingly, the composite target provided by the invention can not only reduce or even avoid the bending, deformation, cracking and other phenomena of the ruthenium-containing target in the sputtering process, but also increase the chance of the ruthenium-containing target to continue to be used, further enhancing its commercial value.

The above-mentioned embodiments are only given for the convenience of explanation, but the embodiments are not used to limit the scope of the patent application of this creation; any other changes, modifications, etc. that do not deviate from the disclosed content of this creation should be included in the patent scope covered by this creation.

Claims (14)

A composite target material, comprising: A support target material; and A ruthenium-containing target material, the ruthenium-containing target material being bonded to the support target material; wherein the support target material comprises a first component capable of solid solution with ruthenium, and the thermal conductivity of the first component is greater than 50 W/m·Kelvin; based on the total number of atoms of the support target material as a whole, the total content of the first component is 70 atomic percent to 100 atomic percent; The ruthenium-containing target material comprises ruthenium and an oxide component; based on the total number of atoms of the ruthenium-containing target material as a whole, the total content of the oxide component is 20 atomic percent to 42 atomic percent; wherein the ratio of the flexural strength of the ruthenium-containing target material to the support target material is 0.1 to 0.8; The ratio of the linear expansion coefficient of the ruthenium-containing target to that of the supporting target is 0.8 to 1.2. The composite target as described in claim 1, wherein the flexural strength of the supporting target is greater than 700 MPa. The composite target as described in claim 1, wherein the first component comprises cobalt, iron, chromium, molybdenum, nickel or a combination thereof. A composite target as described in claim 3, wherein the supporting target further comprises a second component; the second component comprises aluminum, zinc, tin, copper, palladium, tungsten, silicon, niobium, magnesium or a combination thereof; based on the total number of atoms in the supporting target as a whole, the total content of the second component is greater than 0 atomic percent and less than or equal to 30 atomic percent. The composite target as described in claim 1, wherein the oxide component is selected from the group consisting of aluminum oxide, titanium oxide, silicon oxide, boron oxide, cobalt oxide, chromium oxide, magnesium oxide, niobium oxide, tungsten oxide, manganese oxide, zirconium oxide and combinations thereof. The composite target as described in any one of claims 1 to 5, wherein the ruthenium-containing target further comprises an additive component; the additive component comprises platinum, cobalt, chromium, boron, titanium, ruthenium, aluminum or a combination thereof. A composite target as described in claim 6, wherein the total content of the added component is greater than or equal to 18 atomic percent and less than or equal to 47 atomic percent based on the total number of atoms of the entire ruthenium-containing target. A method for preparing a composite target, comprising: Joining a support target and a ruthenium-containing target to obtain the composite target; wherein the support target comprises a first component capable of solid solution with ruthenium, and the thermal conductivity of the first component is greater than 50 W/m·Kelvin; based on the total number of atoms of the support target as a whole, the total content of the first component is 70 atomic percent to 100 atomic percent; the ruthenium-containing target comprises ruthenium and an oxide component; based on the total number of atoms of the ruthenium-containing target as a whole, the total content of the oxide component is 20 atomic percent to 42 atomic percent; wherein the ratio of the flexural strength of the ruthenium-containing target to the support target is 0.1 to 0.8; the ratio of the linear expansion coefficient of the ruthenium-containing target to the support target is 0.8 to 1.2. A method for preparing a composite target as described in claim 8, wherein the oxide component is selected from the group consisting of aluminum oxide, titanium oxide, silicon oxide, boron oxide, cobalt oxide, chromium oxide, magnesium oxide, niobium oxide, tungsten oxide, manganese oxide, zirconium oxide and combinations thereof. A method for preparing a composite target as described in claim 8, wherein the first component comprises cobalt, iron, chromium, molybdenum, nickel or a combination thereof. A method for preparing a composite target as described in any one of claims 8 to 10, wherein the method for bonding the supporting target to the ruthenium-containing target comprises: firstly forming the ruthenium-containing target from a raw material mixture through a sintering process; and then placing the ruthenium-containing target on the supporting target for a sintering bonding process. A method for preparing a composite target as described in any one of claims 8 to 10, wherein the method for joining the supporting target and the ruthenium-containing target comprises: placing a raw material mixture for preparing the ruthenium-containing target directly on the supporting target, and then performing a sintering process. A method for preparing a composite target as described in claim 12, wherein the raw material mixture of the ruthenium-containing target comprises a ruthenium raw material, an oxide component raw material and an additive component raw material; the ruthenium-containing target further comprises an additive component; the additive component raw material comprises a platinum raw material, a cobalt raw material, a chromium raw material, a boron raw material, a titanium raw material, an uranium raw material, an aluminum raw material or a combination thereof; the additive component comprises platinum, cobalt, chromium, boron, titanium, uranium, aluminum or a combination thereof. A method for manufacturing a composite target as described in claim 11, wherein in the sintering and bonding process, the sintering temperature is 650° C. to 1250° C., and the sintering pressure is 220 bar to 1300 bar.

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