CN1777703A

CN1777703A - Homogenous solid solution alloys for sputter-deposited thin films

Info

Publication number: CN1777703A
Application number: CN03825515.4A
Authority: CN
Inventors: M·E·汤马士; 李逸亨
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2002-10-08
Filing date: 2003-09-26
Publication date: 2006-05-24
Also published as: US20040123920A1; TW200420742A; JP2006524290A

Abstract

The invention includes a sputtering component comprising a sputtering surface. At least 99 atomic % of the sputtering surface consists of a single phase corresponding to a solid solution of two or more elements in elemental form. Additionally, an entire volume of the sputtering component can consist of the single phase corresponding to the solid solution of the two or more elements in elemental form. The invention encompasses methods of forming mixedmetal materials utilizing one or more of a reduction process, electrolysis process and iodide process.

Description

Homogeneous solid solution alloys for sputter deposited thin films

Technical Field

The present invention relates to sputtering components, such as physical vapor deposition targets; and a method of manufacturing a sputtering component. The invention also relates to sputter-deposited thin films.

Background

Physical vapor deposition methods are commonly used to form thin films of materials. FIG. 1 shows a schematic view of a portion of an exemplary physical vapor deposition apparatus 10. The apparatus 10 includes a backing plate 12 having a sputter target 14 bonded thereto. A wafer 16 of semiconductor material is disposed in the apparatus 10 and is spaced apart from the target 14. The surface 15 of the target 14 is a sputtering surface. In operation, sputtered material 18 leaves the surface 15 of the target 14 and forms a coating (or film) 17 on the wafer 16.

The backing plate/target assembly of fig. 1 is shown in fig. 2 and 3 in a side sectional view and a top view, respectively. The backing plate 12 and target 14 are interfaced together. The interface may comprise a diffusion bond, or a braze bond, between the backing plate and the target.

The backing plate/target assembly shown in fig. 1-3 is an exemplary construction, and it should be understood that the invention described below can be used in target assemblies other than that shown in fig. 1-3. For example, the present invention may be used in a one-piece target assembly (where one-piece refers to a target machined or manufactured from a single piece of material, not bonded to a backing plate). It should also be understood that the physical vapor deposition process, sputtering, may occur from the surface of other components besides the target (e.g., coils). For purposes of clarifying the present specification and appended claims, the term "sputtering component" refers to any component from whose surface material is sputtered during a physical vapor deposition process.

Metals are often used as sputtering target materials in the manufacture of electronic devices, such as integrated circuits associated with semiconductor structures. The metals take the form of alloys in certain applications. Metals can be used, for example, to form contacts and interconnects in microelectronic devices, as well as to form anti-reflective coatings, etch stop layers, copper diffusion barrier layers, metal gate electrodes, and the like.

The sputter deposition of metallic materials using alloys instead of pure elements has many advantages. For example, alloying elements may reduce electromigration effects during deposition of conductive films (an exemplary alloy is Al-Cu)_x). The alloy can provide a target materialPhysical and mechanical Strength of the Material (an exemplary alloy is Ti-Zr)_x). The alloy may form a passivation layer in a microelectronic circuit (an exemplary alloy is Cu-Al)_x). The alloy can reduce the magnetic effect of the target material (an exemplary alloy is Ni-V)_x). The alloys allow the specific electrical properties of the metals to be exploited in order to function as gate electrodes for transistor devices, for example, Complementary Metal Oxide Semiconductor (CMOS) devices. Additionally, the alloy can reduce arcing by keeping the grain size small. For purposes of illustration, the subscripts used to denote the ingredients (i.e., x, y, and z) are greater than zero, but are not limited to particular values unless specifically indicated.

Conventional alloying techniques have met with some success in forming suitable sputter target structures. However, secondary phases or precipitates can form in the sputter target material, which limits the suitability of the material for various applications or inhibits achievement of desired properties with thesputter target material. In addition, the differential erosion rates between the primary target constituent material and the secondary phase can form sharp boundaries or protruding precipitates on the sputtering face of the target, leading to arcing and/or to undesirable defects in the sputter-deposited film formed on the semiconductor wafer.

Disclosure of Invention

The present invention relates to the formation and use of single phase solid solution alloys of elemental metals. The alloys are useful in sputtering targets and other sputtering components. In particular aspects, the alloying elements may form a complete series of solid solutions throughout the composition range of the alloying elements. In other applications, the alloying elements may form a series of solid solutions within a wide range of various compositions of the elements, and the sputtering component or other structure is formed from suitable alloying compositions such that a solid solution between the alloying elements exists during formation and use of the structure. Sputtering components formed according to the present invention preferably have only a single phase, and thus no secondary ordered or other secondary phase structures are formed in the component. The secondary ordered structures are generally not present in the sputtering components of the present invention at temperatures between solid state and room temperature. It is particularly desirable to eliminate precipitated phases completely from the sputtering components of the present invention.

The single phase alloys of the present invention have improved properties compared to multi-phase alloys. For example, solid solution strengthening in the solid solution alloys of the present invention can improve the mechanical properties of the alloys. The single phase alloy of the present invention can form a high strength sputtering target that is more resistant to reversion and grain growth than sputtering targets having secondary phases. In addition, sputtered materials comprising single phase alloys can have a continuous range of physical and mechanical properties achieved by grading the constituent element ratios throughout the range of compositions forming solid solutions.

One exemplary application of such materials is to allow transistor gates of integrated circuit devices to have a range of work functions. Eliminating secondary phases on the sputtering surface of the target can reduce, and in certain cases eliminate, random or premature arcing along the sputtering surface during sputtering operations. The use of single phase alloys in target materials (or other sputtering components) of the invention can also reduce the diffusion characteristics of the target material (or other sputtering component) and the diffusion characteristics of sputter-deposited thin films from the target material (or other sputtering component).

One exemplary sputtering component of the present invention consists of a single phase, which corresponds to a solid solution of two or more elements in elemental form. These elements are indicated in elemental form to indicate that these elements are not included in the compound. For example, if nickel is described as having an elemental form, this indicates that the nickel is not present as a nickel compound (exemplary nickel compounds include nickel silicide and nickel aluminide).

In one aspect, the invention relates to a method of forming a single-phase solid solution mixed-metal material. A solid solution may include a base element and one or more additional elements, or may have two or more elements with equal atomic numbers. For purposes of illustrating the present disclosure and claims that follow, a material having a first element M as the predominant element in the materialmay be referred to as having a base element. In other words, the M-based material has a main element M. "major elements" are defined as elements that are present in higher concentrations than any other element in the material. The predominant element may be the predominant element in the material, but may be less than 50% of the material. For example, the first element M may be the main element of the material, wherein the element M accounts for only 30%, as long as the concentration of the other elements contained in the material is not greater than or equal to 30%.

The first element M present in the solid solution material may also be equal to or less in atomic number than the one or more additional elements Q. In this context, Q may represent a single element in a binary composition, or may be a combination of two or more elements in a solid solution in another composition. Thus, MQ may be a binary alloy, or may be a ternary or higher alloy.

In an exemplary process of forming a solid solution mixed-metal ingot, such an ingot can be formed by combining a mixture of a first metal halide (M-halide) and at least one other metal halide (Q-halide) with a reducing agent to produce a mixed-metal product. The mixed-metal product is then melted to form a molten mixed-metal (M-Q) material. The molten mixed-metal material is cooled to form a mixed-metal ingot comprising a solid solution of M-Q. The ingot comprises titanium and at least one other metal. The ingot has pure M and at least 99.95% of at least one other metal Q.

In another aspect, the invention relates to a method of electrolytically forming a mixed-metal solid solution material. A mixture of a first element M and at least one other metal Q is electrodeposited as a mixed metal (M-Q) product. The mixed-metal product is melted to form a molten mixed-metal material. The molten mixed-metal material can be cooled to form a single-phase solid solution mixed-metal ingot. The ingot comprises M and at least one other metal Q. The ingot can have a purity M and at least one other metal Q of at least 99.95%.

In another aspect, the invention relates to an iodide transfer method for forming a single phase solid solution mixed-metal material. The mixture containing the first element M is set in a reaction apparatus with iodine gas and a heated substrate. M reacts with iodine gas to form an iodide, which is subsequently transferred to the heated substrate. The heat of the substrate decomposes the iodide and forms a mixed metal product comprising M. The mixed-metal product can be melted to form a molten mixed-metal (M-Q) material, which is subsequently cooled to form a solid solution mixed-metal ingot.

Drawings

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of a portion of a prior art physical vapor deposition apparatus;

FIG. 2 shows a schematic cross-sectional side view of the prior art target/support plate structure shown in FIG. 1, which corresponds to ENDURA, available from Honeywell International Inc^TMThe structure of the device;

FIG. 3 is a top view of the prior art target/backing plate structure shown in FIG. 2;

FIG. 4 is a flow chart showing a method of the present invention;

FIG. 5 is a flow diagram illustrating an exemplary reduction process of the present invention;

FIG. 6 is a schematic cross-sectional view of an apparatus used in the electrolytic process of the present invention;

FIG. 7 is aschematic cross-sectional view of an iodide process of the present invention;

FIG. 8 is a block diagram of the melting and ingot forming process of the present invention.

Detailed Description

The present invention includes sputtering components (e.g., sputtering targets) that comprise, consist essentially of, or consist of a solid solution of two or more elements in elemental form. In particular aspects, the elements used by the sputtering component can all belong to the same group of the periodic table of elements. However, it is to be understood that other aspects of the invention also relate to at least a portion of the elements selected from different groups of the periodic table. All element group number designations used in this description employ the number system (1-18) under the current version of the international union of theoretical and applied chemistry (IUPAC).

It is advantageous for the sputtering component to consist essentially or entirely of a single phase, at least because: (1) leading to an increase in the mechanical strength of the component; (2) premature arcing of the component surface is reduced, or even eliminated, during sputtering; and (3) reducing problems associated with diffusion of sputter-deposited films within and of the component.

In a particular aspect, at least 99 atomic% of the surface of the sputtering component is single-phase (e.g., surface 15 of sputtering target 14 shown in fig. 1). A single phase corresponds to a solid solution of two or more elements in elemental form. In another aspect, at least 99.9% of the sputtering surface consists of a single phase; preferably the entire sputtering face consists of a single phase. Generally, the sputtering component has a single composition throughout the volume of the component, and thus, 99 atomic% of the entire volume of the sputtering component can be a single phase, in particular aspects 99.9% can be a single phase, and in another aspect, the entire volume of the sputtering component can be composed of a single phase. Alternatively, the sputtering component (e.g., target 14 of FIG. 1) can have a total mass, which can be understood to be the entirety of the sputtering component. Desirably, at least 99 atomic% of the total mass is a single phase as described above, in other aspects, at least 99.9% of the total mass is a single phase, and in other aspects, it is desirable that the total mass comprises only a single phase.

It should be appreciated that in applications where the sputtering component is comprised of less than 100% single phase, a small amount of secondary material is contained in the target. Such secondary materials may be provided in several million parts concentrations to improve specific properties of the target or of sputter-deposited films of the target. For example, low concentrations of materials can be included as dopants in a physical vapor deposition target that are ultimately used to tune various physical properties of a sputter-deposited film (exemplary physical properties include the barrier properties of the film to diffusion of particular materials, as well as the electrical properties of the film).

The single phase bonded element of the sputtering component can be a metallic element and can be selected from group 1 of the periodic table, and in particular aspects can be selected from only group 1 of the periodic table. For example, the elements may include Cs and Rb.

In other aspects, the elements in the single phase of the sputtering component include at least two elements selected from group 11 of the periodic table, and in particular aspects, the elements are selected from only group 11 of the periodic table. For example,elements M and Q may include Ag and Cu.

Alternatively, the single phase in the sputtering component can include two or more elements from group 4 of the periodic table, and in particular aspects can include only elements from group 4 of the periodic table. For example, the sputtering component can include Zr and Hf. It should be noted that titanium is excluded from the particular sputtering components of the present invention. It should also be noted that titanium may be included in some sputtering components, alloys, and films; particularly where the composition, alloy or film of the component includes three or more elements.

The two or more elements M and Q in the single phase of the sputtering component can include at least two elements selected from group 5 of the periodic table, and in particular aspects, the elements are selected from only group 5 of the periodic table. For example, elements M and Q may be selected from Ta, Nb, and V.

The two or more elements in the single phase of the sputtering component can include at least two elements selected from group 6 of the periodic table, and in particular aspects, the elements are selected from only group 6 of the periodic table. Thus, the elements M and Q may be selected from Cr, Mo and W.

In other aspects, the two or more elements in the single phase of the sputtering component can include at least two elements selected from groups 8, 9, and 10 of the periodic table, and in particular aspects, the elements are selected from only groups 8, 9, and 10 of the periodic table. (note that groups 8, 9 and 10 correspond to a single group VIIIB under the previous IUPAC specifications). Thus, the solid solution used for the sputtering component can be selected from the group consisting of Fe/Os, Fe/Ru, Co/Ir, Co/Rh, Ir/Rh, Ni/Pd, Ni/Pt, Co/Ni, and Pd/Pt (solid solutions are described using solid solution constituents, and the method of listing only constituents does not have a specific stoichiometric representation). Of course, the solid solutions described are only a small fraction of the total solid solution that can be formed from two or more elements of groups 8, 9 and 10. Even though each solid solution described comprises only two elements, it is understood that the solid solution used for the sputtering component may also comprise 3 or more elements.

As noted above, the sputtering components of the present invention comprise a mixture of elements of different groups of the periodic table. For example, single phase solid solutions of the sputtering components of the present invention can include Cu/Ni, Ta/Mo, Ta/W, or Cr/Fe.

Some of the components listed above have a solid phase in all possible ranges of the mixture of elements M and Q, while other components have a solid phase only in some ranges of the mixture of elements M and Q. For example, the Co/Ni composition is a single phase in a partial range of the phase diagram, and similarly, Ni/Pd, Ni/Pt, Cu/Ni and Cr/Fe are solid solutions in a partial range of the phase diagram. For purposes of the present invention, the relative concentrations of the elements of the sputtering component are preferably selected such that the elements form a single phase solid solution within the component during formation of the component and remain in a single phase during operation of the component. It may be desirable for a single phase to also be present in the sputter-deposited film of the component.

In one exemplary aspect, the invention includes a sputtering component comprising a sputtering surface. At least 99 atomic% of the sputtering surface is a single phase corresponding to a solid solution of two or more elements in elemental form. The solid solution contains a first element M and one or more additional elements Q. In particular instances, M and Q include at least one element selected from the same group of elements, or from groups 8, 9, and 10. Where Q is 2 or more elements, all elements comprised by Q may be from the same group or groups 8, 9 and 10. Alternatively, Q may comprise elements from different groups.

In some cases, at least 99.9 atomic% of the sputtering face can be composed of a single phase, and in some aspects, the entire sputtering face is composed of a single phase.

The sputtering component can be in the form of a physical vapor deposition target. The physical vapor deposition target can have a total volume, and at least 99 atomic% of the total volume can consist of the single phase, and at least 99.9 atomic% of the total volume can consist of the single phase, or the entire total volume can consist of the single phase.

The invention includes sputter-deposited thin films of single-phase solid solution sputtering components. The deposited film may also comprise a single phase solid solution and may in some cases comprise the same percentage of solid solution material as the original component.

The two or more elements of the sputtering component can include at least two elements selected from group 1 of the periodic table, and can include only elements selected from group 1 of the periodic table. The two or more elements may include Cs and Rb. The invention can include a sputter-deposited film of a sputtering component including at least two elements selected from group 1 of the periodic table.

The two or more elements of the sputtering component can include at least two elements selected from group 11 of the periodic table, and can include only elements selected from group 11 of the periodic table. The two or more elements may include Ag and Cu. The invention can include sputter depositing a thin film from a sputtering component that includes at least two elements selected from group 11 of the periodic table.

The two or more elements of the sputtering component can include at least two elements selected from group 4 of the periodic table, and can include only elements selected from group 4 of the periodic table. The two or more elements may include Zr and Hf. The invention can include sputter depositing a thin film from a sputtering component that includes at least two elements selected from group 4 of the periodic table.

The two or more elements of the sputtering component can include at least two elements selected from group 5 of the periodic table, and can include only elements selected from group 5 of the periodic table. The two or more elements may include an element selected from Ta, Nb, and V. The invention can include sputter depositing a thin film from a sputtering component that includes at least two elements selected from group 5 of the periodic table.

The two or more elements of the sputtering component can include at least two elements selected from group 6 of the periodic table, and can include only elements selected from group 6 of the periodic table. The invention can include sputter depositing a thin film from a sputtering component that includes at least two elements selected from group 6 of the periodic table.

The two or more elements of the sputtering component can include at least two elements selected from groups 8, 9, and 10 of the periodic table, and can include only elements selected from groups 8, 9, and 10 of the periodic table. The two or more elements may be selected from Fe/Os, Fe/Ru, Co/Ir, Co/Rh, Ir/Rh, Ni/Pd, Ni/Pt, Co/Ni and Pd/Pt. The invention can include sputter depositing a thin film from a sputtering component that includes at least two elements selected from groups 8, 9, and 10 of the periodic table.

As other examples, the sputtering component can comprise, consist essentially of, or consist of a solid solution selected from Cu/Ni, Ta/Mo, Ta/W, and Cr/Fe. The thin film may be formed from a target comprising, consisting essentially of Cu/Ni, Ta/Mo, Ta/W or Cr/Fe.

The present invention includes methods of forming mixed-metal materials, and in particular applications, to novel methods of forming ingots of the above-described metal solid solution mixtures. In particular embodiments, a mixed metal feedstock comprising M and Q is formed by one or more of a reduction process, an electrolysis process, or an iodide process, which feedstock is subsequently melted to form a homogeneous molten metal mixture. The molten mixture is then cooled to form a mixed-metal ingot comprising a solid solution of M and Q. The ingot is then formed into a material having a solid solution mixed-metal composition desirable. For example, an ingot can be used to form a sputtering target. Note that various reduction processes, electrolysis processes, or iodide processes are described in U.S. patent nos. 6063254 and 6024847; and U.S. patent application No. 08/994733. U.S. Pat. Nos. 6063254 and 6024847 and U.S. patent application No.08/994733 are incorporated herein by reference.

In certain applications, the mixed metal in the ingot may be an M-based material (i.e., the first element M is the predominant element in the mixed metal), and in other applications, a majority of the mixed metal is not a single element. The metal mixture may be a binary component or a higher-order component as described above, and the ratio of the elements is preferably within a range suitable for forming a solid solution. The M-based mixture or mixtures containing equal atomic amounts of 2 or more elements can ultimately be used to form a sputtering target.

An exemplary use of the solid solution sputtering target of the present invention is the sputter deposition of thin films on semiconductor substrates. In particular examples, the deposited film may comprise, may consist essentially of, or consist of a solid solution. The film can serve as a barrier to migration of metal from metal-containing components to other related components of the semiconductor substrate. In particular, the thin film may be disposed between the metal-containing component and other components of the semiconductor substrate and may be used to block migration of metal from the metal-containing component to other related components of the semiconductor substrate.

To assist in interpreting the claims that follow, the terms "semiconductor substrate" and "semiconductor body" are defined to mean any structure comprising semiconductor material, including, but not limited to, bulk semiconductor materials such as semiconductor wafers (either monolithic or assembly comprising other materials), and layers of semiconductor material (either monolithic or assembly comprising other materials). The term "substrate" refers to any supporting structure, including but not limited to the semiconductor structures described above. An exemplary semiconductor material is silicon, such as monocrystalline silicon.

Particularly useful barrier layers are those comprising, consisting essentially of, for example, Ti_xHf_yN_zOr Ta_xV_yN_zIs/are as followsA layer, such layer may be made of, consist essentially of Ti_xHf_yAnd/or Ta_xV_y(wherein x, y and z are not limited to any particular values).

Other useful layers or films that can be formed from the single-phase solid solution targets of the invention can include Zr_xHf_yN_zAnd/or Ta_xMo_yN_zWherein x, y, and z are not limited to any particular value and are each greater than zero. Such a layer may consist of, consist essentiallyof Zr_xHf_yAnd Ta_xMo_yForming a sputtering target of (1). The single-phase solid solution target of the present invention comprising the above-described composition can also be used to form a conductive layer and an insulating protective layer (e.g., a nitride layer). Gate materials having a particular work function can be formed by varying the ratio of M and Q (and/or the ratio of the elements that Q comprises) in a single phase target of the invention. This adjustment technique of the ratio of constituent elements can also be used to design the target to achieve the desired physical, mechanical and/or thermal properties, including resistivity, mechanical strength and coefficient of thermal expansion, of the deposited film or layer.

The method of the present invention is shown in the flow chart of fig. 4. In an initial step 20, a mixture of metallic elements is provided. The mixture generally includes a first metal M and one or more additional elements Q, with titanium and zirconium being excluded in particular embodiments. The elements may be in elemental form or provided in the form of molecular constituents in the mixture step 20. For example, M may be an element M or an M halide (i.e., MCl)_x) Is provided in the form of (1).

A mixing step 20 is provided for one or more of a reduction process 22, an electrolysis process 24, or an iodide process 26. In the schematic of fig. 4, reduction process 22 is shown connected by a dashed arrow to electrolysis process 24, which electrolysis process 24 is in turn shown connected by a dashed arrow to iodide process 26. The dashed arrows show that processes 22, 24, and 26 may be selectively connected to each other sequentially. For example, the material from step 20 may be provided to a reduction process 22, then sequentially from reduction process 22 to an electrolysis process 24, and sequentially from electrolysis process 24 to an iodide process 26.

Alternatively, the material of step 20 may be provided to a reduction process 22 and then not subjected to an electrolysis process 24 or an iodide process 26. Additionally, although the arrows between

processes

22, 24, and 26 are shown as proceeding in a particular direction, it should be understood that the processes connected by the dashed arrows may be connected in reverse of that shown. For example, material from electrolytic process 24 may be provided to reduction process 22 instead of flowing from reduction process 22 to electrolytic process 24 as shown. However, the flow shown is the preferred flow direction because electrolytic processes are typically used to further purify the material after the reduction process, and the iodide process is considered to be a process that can perform additional purification beyond that achieved by electrolytic process 24 or reduction process 22.

After the material has undergone one or more of

processes

22, 24, and 26, the material is considered a product. The product is subjected to step 28, which includes melting the product and then cooling the molten material to form an ingot. The ingot may have a mixture of contained elements that reflects at least a portion of the original mixture of metallic elements in the composition of step 20. However, the final composition of the ingot formed in step 28 has a different stoichiometric relationship than the mixture of step 20, and the kinetics and/or thermodynamics of

processes

22, 24 and 26 favor one metallic material over another.

The process of

steps

22, 24, 26 and 28 is described in more detail in fig. 5-8. Referring first to fig. 5, the reduction process of step 22 is further illustrated. The illustrated process forms a mixed-metal material that includes or consists essentially of an MQ alloy. First, MCl is mixed_xAnd QCl_xAnd a reducing agent (e.g., sodium or magnesium metal). The resulting exothermic reaction forms an alloy of M and Q. Relative proportions of M and Q in the alloy and MCl used_xAnd QCl_xThe ratio of the two is approximately proportional. Thus, M-based binary alloys can be made by using a higher proportion of MCl_xAnd QCl_xChinese character 'lai' shapeThe M-based alloy including two or more elements can be formed by allowing MCl_xThere is a higher percentage of chloride relative to any one of the elements included in Q. Although the invention has been described by way of example with a metal chloride as the reducing agent, it will be appreciated that other metal halides than metal chlorides may be used.

The reducing agent used in the reduction process shown in fig. 5 is typically in gaseous or liquid form. For example, the reducing agent may include molten sodium, QCl_xAnd MCl_xMay be in gaseous form. Thus, the reactions occurring in the reduction process can be summarized as the following reactions (1) and (2), wherein S is a solid phase; l is the liquid phase and g is the gas phase.

(1)

(2)

M(s) and Q(s) may form a mixed metal sponge. This sponge may then be melted and cooled to form an ingot, or may be used as a feedstock for the electrolysis process 24 or the iodide process 26 of fig. 4.

If the formed alloy is an M-based alloy, the overall Q metal content in the material resulting from the process of FIG. 4 may be any value so long as Q includes an element that does not equal or exceed the content of M. In particular aspects, the amount of Q is in the range of 0.001% to 50%, for example 0.001% to 10%. In particular embodiments, the overall Q metal content in the material may be at least 0.01%, in other embodiments at least 0.1%, in other embodiments at least 1%, and in other embodiments at least 2%. The amount of Q in the mixed metal material is provided to have a sufficient concentration such that Q is present at a concentration greater than 5ppm in the material purified to 5N5, greater than 50ppm in the material purified to 4N5, greater than 500ppm in the material purified to 3N5, or greater than one thousandth in the material purified to 3N.

If the mixed-metal material is subsequently melted and used to form an ingot in step 28 shown in fig. 4, and the melting is performed without an intervening process occurring between the reduction process and the melting process, the relative proportion of Q in the formed ingot is the same as the relative proportion in the mixed-metal product formed by the reduction process of fig. 5.

If the resulting alloy is not an M-based alloy, Q comprises at least one additional element atomically equivalent to M. The additional element contained in Q may be present in the alloy less than or equal to M in atomic number.

In a particular embodiment, the reduction process of fig. 5 may form an alloy including M and Q, as shown. In such a process, the material may be an M-based, where the only other metal other than M is the element comprised by Q.

Referring next to fig. 6, the electrolytic process 24 of fig. 4 is described in more detail. Specifically, FIG. 6 shows an apparatus 50 that can be used in the electrolytic process of the present invention. The apparatus 50 includes a furnace 52. An anode 54 and a cathode 56 are provided in the furnace 52. A metal feedstock 58 is provided on the anode 54. The metal feedstock 58 may include M and one or more additional metals Q. In particular embodiments, the metal feedstock may include two or more elements selected from groups 1, 4, 5, 6, or 11 of a single periodic table. In alternative embodiments, the metal feedstock may include two or more elements selected from groups 8, 9, and 10 of the periodic table. In other embodiments, the metal feedstock may include one or more elements selected from different groups of the periodic table. Exemplary raw materials include metals from different groups, including raw materials consisting of one of the combinations Cu/Ni, Ta/Mo, Ta/W or Cr/Fe.

An electrolyte 60 is disposed between the anode and the cathode. The electrolyte may include a salt, such as sodium chloride or magnesium chloride, that is in a molten state due to the temperature maintained by the furnace 52.

In operation, a voltage is applied between the anode 54 and the cathode 56, and the electrolyzed metal is transferred from the mixture 58 to the cathode 56, forming a mixed metal product 62 at the cathode 56. Although mixture 58 is described as being disposed on anode 54, it should be understood that anode 54 can be considered electrically connected to mixture 58, and that mixture 58 can be considered to effectively act as an "anode" in an electrolytic transfer reaction. The composition of the mixed-metal product 62 can be determined in part by the voltage applied to the apparatus 50. Thus, apparatus 50 can be used to purify a mixed metal product relative to material 58 disposed at anode 54.

One aspect of the invention is the formation of a mixed metal product at cathode 56. For example, if the primary element is M, the material of cathode 56 will preferably include at least 0.001% of other elements other than M. The number and type of elements provided at the cathode 56 may be determined by the voltage applied to the device 50 and the starting material 58. In particular, if M is used²⁺The voltage limit of +/-0.7V of reduction potential of/M conversion, and the use of M²⁺The product 62 may incorporate a greater number of elements than the ± 0.5 volt limit of the reduction potential of the/M conversion. The voltage limit of the reduction potential of the primary element is preferably no more than 0.7 volts to avoid adding excessive impurities to the product 62.

Referring next to fig. 7, an iodide process for step 26 of fig. 4 is schematically illustrated. In particular, fig. 7 shows an apparatus 100 comprising a reaction chamber 102. The feedstock 106 is in the reaction chamber 102 and the heated substrate 104 extends into the reaction chamber 102. Feedstock 106 includes at least 2 different metals, and may include, for example, a primary metal M. An iodine gas 108 is provided in the reaction chamber 102. In operation, iodine gas 108 migrates metal from feedstock 106 to heated substrate 104. Metal is then deposited on the substrate 104 to form the product 110. The migration of metal from feedstock 106 to heated substrate 104 is described with reference to equations (3) - (5), and in particular, with respect to forming an exemplary metal.

(3)

(4)

(5)

Thus, the metal M is converted to iodide, which is then decomposed on the heated substrate 104 to deposit the M material 110. The above reactions are exemplary reactions only, and it is understood that the chemical reactions of metal migration in apparatus 100 may include other reactions in addition to, or instead of, those described above.

The rate of material transfer from the feedstock 106 to the product 110 depends on the temperature difference between the feedstock 106 and the substrate 104, the concentration of iodine, the kinetics of the reaction of the particular metal with iodine to form iodide, and the kinetics of the reaction of the particular metal iodide to decompose to form the metallic element. Thus, if feedstock 106 includes a mixture of elements, product 110 may include a mixture having a different stoichiometric value than the initial feedstock 106, such as may result from differences in iodide formation kinetics for different metal iodides, and/or differences in iodide decomposition kinetics for different metal iodides.

Feedstock 106 may include two or more elements selected from a single group 1, 4, 5, 6, or 11 of the periodic table. In alternative embodiments, the metal feedstock 106 may include two or more elements selected from groups 8, 9, and 10 of the periodic table. In other embodiments, the metal feedstock may include one or more elements selected from different groups of the periodic table. Exemplary raw materials containing metals from different groups include raw materials consisting of one of the combinations Cu/Ni, Ta/Mo, Ta/W or Cr/Fe.

Likewise, product 110 may include two or more elements selected from a single group 1, 4, 5, 6, or 11 of the periodic table. In alternative embodiments, the product 110 may include two or more elements selected from groups 8, 9, and 10 of the periodic table. In other embodiments, the product 110 may include one or more elements selected from different groups of the periodic table. Exemplary products containing metals from different groups include products composed of one of the combinations Cu/Ni, Ta/Mo, Ta/W or Cr/Fe.

FIG. 8 is a block diagram illustrating a system for the process of step 28 of FIG. 4. Specifically, FIG. 8 shows a system 150 that includes a feed port 154, a cooled hearth 156, and a mold 158. In operation, the supplied material is poured through the feed opening 154 and melted by vacuum melting (e.g., by an electron beam gun) to form a homogeneous molten mixture of the elements in the supplied material. The molten mixture is then poured into a cooled hearth 156 and then into a mold 158. The mold 158 may be in the form of an ingot clad. Thus, the material flowing into the mold 158 may cool and form an ingot. The ingot preferably has a single phase solid solution composition in which the elements are initially present in the feed material.

The supply material for apparatus 150 may be the product of reduction process step 22 of fig. 4, electrolysis process step 24 of fig. 4, or iodide process step 26 of fig. 4. Regardless, the feedstock preferably comprises a mixture of metals, such as an M-based material having at least 0.001% of a non-M metal; or a composition having an equal atomic number of at least one element included in M and Q (an additive element in the composition is not higher than M in atomic%). If the feed material is M-based, the content of the other metal Q in the ingot can be any value, as long as Q comprises an element that does not equal or exceed the M content. In a particular example, the Q content in the ingot may be in the range of 0.001% to 50%, for example, in the range of from 0.001% to 10%. The Q content may be at least 0.01%, and in particular embodiments may be at least 0.1%. Alternatively, if the material in the ingot is a non-single element based material, then at least one metal included in Q will be equal to the number M and any other elements included in Q will be present in a number less than or equal to the number M.

The cooled ingot formed by the process of fig. 8 can be used to form a sputtering target. Sputtering targets comprising solid solutions of metallic elements that are useful in sputtering processes requiring that they be formed into layers or films, including but not limited to barrier layers, conductive layers, gate layers, and insulating protective layers, are particularly useful because the targets can be designed to achieve layers having desired properties, including work function,resistivity, coefficient of thermal expansion, mechanical strength, and the like.

For the present invention to be used in sputtering applications, it may be desirable that the target comprise a single phase solid solution, with the solid solution being present in all elements in the sputtering target. The process of the present invention may allow such solid solutions to be formed. Specifically, because the method of the present invention melts the mixed-metal feedstock, the method of the present invention can form a solid solution mixed-metal ingot, which in turn forms a sputtering target that is fully populated with a solid solution mixed-metal composition.

The prior art has not developed a sputtering target for forming a solid solution containing the composition of one or more of the listed elements, however, the method of the present invention can form such a solid solution target. In certain cases, the target of the present invention may have a single phase solid solution throughout.

Claims

1. A sputtering component comprising a sputtering face, at least 99 atomic% of said sputtering face being a single phase corresponding to a solid solution of two or more elements in elemental form; the two or more elements are selected from groups 1, 5, 6, 8, 9 and 10 of the periodic table.

2. A sputtering component according to claim 1, wherein at least 99.9 atomic% of said sputtering surface is a single phase.

3. The sputtering component of claim 1 wherein the entire sputtering surface is a single phase.

4. The sputtering component of claim1 wherein said sputtering component is a physical vapor deposition target.

5. The physical vapor deposition target of claim 4, wherein the physical vapor deposition target has a total volume, at least 99 atomic percent of the total volume being a single phase.

6. The physical vapor deposition target of claim 5, wherein at least 99 atomic percent of the total volume is a single phase.

7. The physical vapor deposition target of claim 5, wherein the entire total volume is a single phase.

8. The sputter deposited film produced by the sputtering component of claim 1.

9. The sputtering component of claim 1, wherein said two or more elements comprise at least two elements selected from group 1 of the periodic table.

10. The sputtering component of claim 1, wherein said two or more elements are selected from only group 1 of the periodic table.

11. The sputter deposited film produced by the sputtering component of claim 10.

12. The sputtering component of claim 10 wherein said two or more elements comprise Cs and Rb.

13. The sputtering component of claim 1, wherein said two or more elements comprise at least two elements selected from group 5 of the periodic table.

14. The sputtering component of claim 1, wherein said two or more elements are selected from only group 5 of the periodic table.

15. The sputter deposited film produced by the sputtering component of claim 14.

16. The sputtering component of claim 14, wherein said two or more elements are selected from Ta, Nb, and V.

17. The sputtering component of claim 1, wherein said two or more elements comprise at least two elements selected from group 6 of the periodic table.

18. The sputtering component of claim 1, wherein said two or more elements are selected from only group 6 of the periodic table.

19. The sputter deposited film produced by said sputtering component of claim 18.

20. The sputtering component of claim 1, wherein said two or more elements comprise at least two elements selected from groups 8, 9, and 10 of the periodic table.

21. The sputtering component of claim 1, wherein said two or more elements are selected from only groups 8, 9, and 10 of the periodic table.

22. The sputter deposited film produced by the sputtering component of claim 21.

23. The sputtering component of claim 21 wherein said solid solution is a binary combination selected from the group consisting of Fe/Os, Fe/Ru, Co/Ir, Co/Rh, Ir/Rh, Ni/Pd, Ni/Pt, Co/Ni and Pd/Pt.

24. The sputtering component of claim 1, wherein said solid solution is Ta/Mo.

25. The sputtering component of claim 1, wherein said solid solution is Ta/W.

26. The sputtering component of claim 1, wherein said solid solution is Cr/Fe.

27. A sputtering component comprising a single-phase solid solution comprising elemental Cu and elemental Ni.

28. A method of forming a mixed metal product, comprising electrolytically depositing a mixed metal product comprising a mixture of a first metal and at least one other metal, the first metal and one or more of the at least one other metal being selected from groups 1, 5, 6, 8, 9, 10 and 11 of the periodic table; the mixed metal product has a purity of at least 99.95% and includes 0.05% or more of the at least one other metal.

29. The method of claim 28, wherein the first metal and the one or more of the at least one other metal are selected from the same group of the periodic table.

30. The method of claim 29, wherein the first metal and the at least one other metal comprise an element selected from the same group of the periodic table.

31. The method of claim 28, wherein the first metal and the one or more other metals are selected from groups 8, 9, and 10 of the periodic table.

32. The method of claim 31, wherein the first metal and the at least one other metal comprise an element selected from groups 8, 9, and 10 of the periodic table.

33. The method of claim 28, wherein said mixture of elements is selected from Ta/Mo, Ta/W, Cu/Ni and Cr/Fe.

34. A method of forming a mixed metal product, comprising:

providing a mixture of a first metal and at least one other metal to a reaction apparatus having an iodine gas and a heated substrate; said first metal and one or more of said at least one other metal are also selected from groups 1, 4, 5, 6, 8, 9, 10 and 11 of the periodic Table of the elements, wherein said mixture does not include Ti or Zr;

reacting the first metal and the at least one other metal with the iodine gas to form a first metal iodide and the at least one other metal iodide;

transferring the first metal iodide and the at least one other metal iodide to the heated substrate and decomposing the iodide using heat of the substrate and generating a mixed metal product comprising the first metal and the at least one other metal; wherein

The mixed metal product has a purity of at least 99.95%; the mixed metal product includes greater than 0.05% of the at least one other metal.

35. The method of claim 34, wherein the first metal and the one or more at least one other metal are selected from the same group of the periodic table.

36. The method of claim 34, wherein said mixture of elements is selected from Ta/Mo, Ta/W, Cu/Ni and Cr/Fe.

37. The method of claim 34, wherein the first metal and the one or more other metals are selected from groups 8, 9,and 10 of the periodic table.

38. A method of forming a mixed-metal product, comprising combining a mixture of a first metal halide and a second metal halide with a reducing agent to form a mixed-metal product comprising the first and second metals; the first and second metals are selected from groups 1, 5, 6, 8, 9, 10 and 11 of the periodic table; the mixed metal product has a purity of at least 99.95% and includes 0.05% or more of the at least one added metal.

39. The method of claim 38, wherein the first and second metals are selected from Ta/Mo, Ta/W, Cu/Ni, and Cr/Fe.

40. The method of claim 38, wherein the first and second metals are selected from the same group of the periodic table.

41. The method of claim 38, wherein the first and second metals are selected from groups 8, 9, and 10 of the periodic table.