JP2006509109A - High purity nickel / vanadium sputtering component; and method of manufacturing the sputtering component - Google Patents

Abstract

The present invention includes sputtering components, such as sputtering targets, that contain high purity Ni-V. The sputtering component can have a fine grain size throughout, with an exemplary fine average grain size being equal to or less than 40 microns. The present invention also includes a method for producing a high purity Ni-V structure.

Description

Field of Invention

TECHNICAL FIELD This invention relates to high purity nickel / vanadium sputtering components (such as sputtering targets). The present invention also relates to a method of manufacturing a sputtering component.

Background of the Invention Nickel / vanadium materials have numerous applications in the semiconductor industry. For example, these materials can be used in a barrier / adhesive layer for a bump substrate that supports a flip chip, or in a C4 (collapsed, controlled, chip connection) assembly. A typical nickel / vanadium composition is Ni-7V (ie, a composition containing about 7 weight percent vanadium with the remainder being nickel).

  A typical method for forming a nickel / vanadium layer when processing semiconductors is physical vapor deposition (PVD). Specifically, the layers are sputter deposited from a sputtering target. The standard purity of a normal Ni-7V sputtering target is 3N5-3N8 pure (ie, 99.95% to 99.98% pure by weight excluding gas). Purity is typically measured by glow discharge mass spectrometry (GDMS) and / or LECO® (conductivity analysis) methods (LECO® is a registered trademark of LECO Corporation) . The average grain size of conventional Ni-7V sputtering targets is quite large (typically greater than 50 microns).

  The purity and crystal grain size of the sputtering targets limit the quality of the sputter deposited material formed from those targets. Higher purity targets can result in the desired higher purity sputter deposition material. Smaller average grain sizes in these targets can result in better physical and / or chemical homogeneity of the sputter deposited material as well. Therefore, it is desirable to develop an improved Ni-V sputtering target with higher purity and smaller average grain size.

  One limitation on the purity of conventional nickel / vanadium materials is typically imposed by the purity of the vanadium. The nickel / vanadium material is formed by mixing high purity nickel with high purity vanadium. Nickel can have a purity of 4N5 (99.995 wt% excluding gas) or even 5N (99.999 wt% excluding gas), but vanadium is generally 2N5 (gas 99.5% by weight) or less. The purity of available vanadium thus limits the purity of the Ni-V alloy that can be formed. Therefore, there is a desire to develop vanadium materials with improved purity.

  A prior art physical vapor deposition operation that serves as an example will be described with reference to the sputtering apparatus 110 of FIG. 1 to illustrate an exemplary component of a sputtering assembly. Device 110 is an example of an ion metal plasma (IMP) device and includes a chamber 112 having a sidewall 114. Chamber 112 is typically a high vacuum chamber. A target assembly 10 is provided in the upper region of the chamber and a substrate 118 is provided in the lower region of the chamber. The substrate 118 is typically held on a holder 120 that includes an electrostatic chuck. The target assembly 10 will be held by a suitable support member (not shown) that may include a power source. An upper shield (not shown) can be provided to shield the edges of the target assembly 10.

  For example, the substrate 118 can include a semiconductor wafer, such as a single crystal silicon wafer. In certain applications of the device 110, a nickel / vanadium film can cover the surface of the substrate. Thus, the target assembly 10 can include a nickel / vanadium target.

Material 122 is sputtered from the target surface of assembly 10 and directed toward substrate 118.
In general, the sputtered material leaves the target surface in a number of different directions. This can be problematic and the sputtered material is preferably directed in a direction that is relatively orthogonal to the top surface of the substrate 118. Accordingly, a focusing coil 126 is provided in the chamber 112. The focusing coil can improve the orientation of the sputtered material 122 and is shown to direct the sputtered material in a direction that is relatively orthogonal to the top surface of the substrate 118.

  The coil 126 is held in the chamber 112 by the illustrated pin 128 that extends through the side wall of the coil and through the side wall 114 of the chamber 112. The pin 128 is held by a set screw 132 in the configuration shown. The schematic of FIG. 1 shows a pin head 130 along the inner surface of the coil 126 and another set of heads 132 of set screws along the outer surface of the chamber sidewall 114.

A spacer 140 (often referred to as a cap) extends around the pin 128 and is utilized to keep the coil 126 away from the side wall 114.
The device shown in FIG. 1 is only one of many types of PVD devices. Other exemplary devices include those marketed as or by Unaxis, Balzers, Nexx, Ulvac, Annelva and NOVELLUS. Some of these devices utilize circular sputtering targets, while others utilize other target shapes such as square or rectangular designs.

SUMMARY OF THE INVENTION In one aspect, the invention relates to a sputtering component, such as a sputtering target, that includes high purity Ni-V. Sputtered components can have a small average grain size, where an exemplary average grain size is equal to or less than 40 microns.

In one aspect, the present invention includes a method for producing a high purity Ni-V structure.
In the following, preferred embodiments of the present invention will be described with reference to the following accompanying drawings.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In certain aspects, the present invention relates to sputtering components. For purposes of interpreting this disclosure and the claims that follow, the term “sputtering component” refers to any component from which material is sputtered or otherwise removed during physical vapor deposition. A typical sputtering component is a sputtering target, but it should be understood that during physical vapor deposition, sputtering can occur from the surface of other components in addition to the sputtering target (eg, coils, pins or caps) is there. The phrase “sputter component” refers to a sputter component from which material has been sputtered or otherwise removed. As will be appreciated by those skilled in the art, the sputtering target can be formed from a metal blank, plate or slab. The phrase “sputtering target prefab” is used herein to refer to metal blanks, plates, slabs, etc. that are further processed into the sputtering target, and the phrase “sputtering target structure” refers to the sputtering target itself and the sputtering target. Used to generically include prefabs. "Sputtering component prefab" should be understood to refer to the metal blanks, plates, slabs, etc. used to form the sputtering component; and the phrase "sputtering component structure" refers to the sputter component prefab as well as the final finished component. Should be understood to encompass. Sputtering targets encompassed by aspects of the present invention can have any suitable geometry and can be either a bonded assembly or a monolithic sputtering target. Sputtering targets encompassed by aspects of the present invention are not limited, but may be in any form consistent with use in any suitable apparatus, including the apparatus described in the “Background” section of this disclosure. Can be formed.

  In certain aspects, the structure of the present invention has a particular grain size. As used herein, the phrase “average grain size” means the mean grain size measured by standard methods known to those skilled in the art. The average crystal grain size was determined by the ASTM E112 standard test method for measuring the average crystal grain size for the exemplary compositions described herein. Certain structures of the present invention may be less than or equal to about 40 microns throughout the structure, preferably less than, preferably less than about 30 microns, more preferably less than, more preferably less than about 20 microns. It can have a small average crystal grain size. The conversion between micron grain size and ASTM grain size number is listed in Table 1 for certain exemplary grain sizes.

  In certain aspects, the present invention includes a methodology for producing a high purity vanadium composition. An example methodology includes the electrolysis of molten salt. The salt can be an alkali halogen salt such as NaCl, for example. Electrolysis can be repeated multiple, consecutive times to obtain the desired purity of vanadium. In certain aspects of the invention, the composition resulting from this electrolysis is at least 99.995 wt% pure, excluding gas, in vanadium, or excluding gas, in vanadium, Even at least 99.999% pure by weight.

  In certain aspects, the present invention includes a method of making a high purity nickel / vanadium sputtering component. High purity nickel and vanadium raw materials are provided. The nickel source preferably has an overall purity of at least 99.995 wt% excluding gas, more preferably at least 99.999 wt% excluding gas. The vanadium feedstock is at least 99.9% by weight excluding gas, more preferably at least 99.995% by weight excluding gas, and even more preferably at least 99.999% by weight excluding gas. Have purity. The nickel and vanadium materials are melted together to form a molten alloy containing nickel and vanadium. The specific composition of the desired alloy determines the amount of each raw material that is incorporated into the molten alloy. The molten alloy is then cooled to form a nickel / vanadium structure in which nickel and vanadium are at least 99.99%, 99.995% or 99.999% pure (by weight, excluding gases).

The structure formed from the alloy can be a sputtering component prefab (such as a sputtering target prefab) or a sputtering component.
In certain aspects, molten nickel / vanadium alloys may be used in appropriate conventional vacuum melting, such as electron beam, vacuum induction melting (VIM), or vacuum arc remelting (VAR). Cast into high purity nickel / vanadium ingot using technology. An iterative vacuum melting process can be used as desired to improve the overall purity of the ingot and / or to obtain a high purity nickel / vanadium alloy with a homogeneous composition as a result. The resulting high purity Ni-V ingot can be any desired shape (ie, rectangular, square, circular, etc.) and can be any desired size.

  High purity Ni-V ingots can be subjected to thermomechanical processing in order to impart deformation and annealing into the metal of the ingot to give the desired crystal grain size within the metal. An exemplary thermomechanical process utilizes a series of hot and cold rolling steps (in this case, preferably all rolling steps include rolling in the same direction as each other) in combination with annealing. can do. The nickel / vanadium structure resulting from thermomechanical processing can be a nickel and vanadium plate or blank. Such a structure can be a target suitable for bonding to a support plate, or a target prefab suitable for proper machining to form a target structure that can be bonded to a support plate. Can do. Alternatively, the nickel / vanadium structure can be a monolithic target or a target prefab suitable for proper machining to form the structure into a monolithic target. An exemplary thermomechanical processing sequence is given in the example immediately preceding the claims.

  Nickel / vanadium alloys and structures formed in accordance with the methodology of the present invention have an overall metal purity of at least 99.99% nickel / vanadium by weight excluding gas; at least 99.995% (weight excluded gas) Or a total metal purity of nickel / vanadium of at least 99.999% (by weight, excluding gas). In measuring the total metal purity of the nickel / vanadium composition, all detectable impurities are summed (not including elements below or below the detection limit). Standard analytical techniques for measuring purity are GDMS and LECO®. The standard alloy composition in this industry is today Ni-7V. However, the sputtering components described herein can include different amounts of vanadium (ie, greater than or less than 7% by weight). Typically, the nickel / vanadium alloys of the present invention contain about 4 weight percent vanadium (the balance of the alloy is nickel) to about 10 weight percent vanadium (the balance of the alloy is nickel). The results of the analysis of the nickel / vanadium alloy formed according to one aspect of the present invention are given in Table 2. This alloy contains 6.64 weight percent vanadium.

  An exemplary target assembly that can be formed according to the methodology of the present invention is described with reference to FIGS. The assembly includes a support plate 12, a target 14, and a joint 16 between the target and the support plate. The joint can be a diffusion joint or can include an interlayer material (eg, solder). Target 14 may include high purity nickel / vanadium in accordance with various aspects of the present invention. This assembly 11 can be utilized as a target assembly 10 in a deposition apparatus of the type described above with reference to FIG.

  Another exemplary target assembly 20 that can be formed in accordance with the methodology of the present invention is described with reference to FIGS. This assembly includes a monolithic target 22. Target 22 may include high purity nickel / vanadium in accordance with various aspects of the present invention. This assembly 20 can be utilized as a target 10 in a deposition apparatus of the type described above with reference to FIG.

  Any component in the sputtering chamber (such as the chamber of FIG. 1) that is exposed to sputtering conditions can release certain materials. Thus, components other than the target can also be considered as sputtering components for certain applications. Members within the chamber that can be sputtering components include, but are not limited to, coils, coverings, clamps, shields, pins and caps. In certain applications, if the material sputters from a non-target sputtering component, it can be problematic in that the material sputtered from the non-target sputtering component can contaminate the material sputtered from the target. . This problem can be mitigated and even prevented if all sputtering components and potential sputtering components in the reaction chamber are formed from the same material as the target. Thus, a target and one or more non-target sputtering components (such as one or more of coils, coverings, clamps, shields, pins, caps, etc.) It would be desirable to form from high purity nickel / vanadium on the surface.

  The nickel / vanadium sputtering component formed in accordance with the present invention can be used to deposit a Ni-V layer over the entire surface of a semiconductor substrate. The Ni-V layer can be used in bump substrate and C4 technology. Furthermore, the layer formed from the high purity small crystal grain size Ni-V sputtering target can also be used for other semiconductor applications other than bump substrate and C4 assembly. For example, these layers can be utilized for silicide formation and high-end coatings in semiconductor applications. Although nickel has been studied for use in silicides and high end coatings in semiconductor applications, the magnetic properties of nickel make pure nickel unsuitable for many such applications. The addition of vanadium to nickel forms a magnetic alloy suitable for semiconductor applications, which is why Ni-7V is used in various applications. However, conventional nickel / vanadium alloys are too low in purity to be suitable for silicides and high end coatings. In contrast, relatively pure Ni-V alloys that can be produced from the sputtering target of the present invention may be suitable for silicide and high end coating applications.

  To produce a high purity Ni-V ingot with reduced ingot thickness (slab thickness can be about 1.5 "(3.81 cm), for example) (1400-2400 One-way hot rolling at high temperatures (such as ° F (760-1316 ° C)); typical deformation rates induced by hot rolling are at least about 90% (ie, slab thickness is ingot The slab is cooled to room temperature and cut into several smaller pieces (eg, at a temperature of 1400-2400 ° F.). ) Subject to hot rolling followed by cold rolling (eg, at about room temperature) to reduce the thickness of the pieces to a final thickness (eg, about 0.35 ″ (0.89 cm)). The hot and cold rolling across these pieces is preferably in one direction and in the same direction as the one-way rolling across the ingot. After hot and cold rolling of the pieces, the pieces are annealed at an elevated temperature (eg, about 1600 ° F. (871 ° C.) for about 1 hour).

1 is a schematic cross-sectional view of an illustrated physical vapor deposition apparatus according to the prior art during a physical vapor deposition (eg, sputtering) process. 1 is a schematic cross-sectional view of an exemplary target / support plate assembly of the present invention. 2 is a top view of the assembly of FIG. 2 with the cross section of FIG. 2 extending along line 2-2 of FIG. 1 is a schematic cross-sectional view of an exemplary monolithic target assembly of the present invention. 4 is a top view of the assembly of FIG. 4 with the section of FIG. 4 extending along line 4-4 of FIG.

Claims (39)

  A nickel-vanadium sputtering component structure comprising at least 99.99% by weight of nickel and vanadium excluding gas.   The sputtering component structure of claim 1, wherein at least 99.995 wt% nickel and vanadium excluding gas.   The sputter component structure of claim 1, wherein at least 99.999 wt% nickel and vanadium excluding gas.   The sputtering component structure according to claim 1 as a sputtering target structure.   The sputtering target structure according to claim 4 as a sputtering target prefab.   The sputtering target structure according to claim 4 as a sputtering target.   A nickel / vanadium sputtering component structure comprising at least 99.99% by weight nickel and vanadium, excluding gases, and having an average grain size equal to or less than about 40 microns throughout the structure A nickel / vanadium sputtering component structure as described above.   The nickel / vanadium sputtering component structure of claim 7 as a sputtering component prefab.   The nickel / vanadium sputtering component structure according to claim 7 as a sputtering component.   The nickel / vanadium sputtering component of claim 9, wherein the average grain size is less than or equal to about 30 microns.   The nickel / vanadium sputtering component of claim 9, wherein the average grain size is equal to or less than about 20 microns.   The nickel / vanadium sputtering component of claim 9, comprising from about 4 weight percent to about 10 weight percent vanadium.   The nickel / vanadium sputtering component of claim 9, comprising about 7 weight percent vanadium.   The nickel / vanadium sputtering component according to claim 9 as a sputtering target.   A layer sputter deposited from the sputtering target of claim 14.   10. The nickel / vanadium sputtering component of claim 9, comprising at least 99.995 wt% nickel and vanadium excluding gases.   The nickel / vanadium sputtering component of claim 16, wherein the average grain size is equal to or less than about 30 microns.   The nickel / vanadium sputtering component of claim 16, wherein the average grain size is less than or equal to about 20 microns.   The nickel / vanadium sputtering component of claim 16, comprising from about 4 weight percent to about 10 weight percent vanadium.   10. The nickel / vanadium sputtering component of claim 9, comprising at least 99.999 wt% nickel and vanadium excluding gases.   The nickel / vanadium sputtering component of claim 20, wherein the average grain size is equal to or less than about 30 microns.   21. The nickel / vanadium sputtering component of claim 20, wherein the average crystal grain size is equal to or less than about 20 microns.   21. The nickel / vanadium sputtering component of claim 20, comprising about 4 weight percent to 10 weight percent vanadium. A method for producing a nickel / vanadium structure comprising:
Providing a nickel material that is at least 99.99 wt% pure, excluding gas, in the nickel;
Providing vanadium material that is at least 99.99 wt% pure, excluding gas, in vanadium;
Melting the nickel and vanadium materials together to form a molten nickel / vanadium alloy from the nickel and vanadium materials; and cooling the nickel / vanadium alloy to exclude gases in the nickel and vanadium; A method as described above comprising the step of forming a nickel / vanadium structure that is at least 99.99% by weight pure.   25. The method of claim 24, wherein the nickel / vanadium structure comprises about 4 weight percent to about 10 weight percent vanadium.   25. The method of claim 24, wherein the nickel / vanadium structure comprises about 7% by weight vanadium.   25. The method of claim 24, wherein the vanadium material is at least 99.995 wt% pure in vanadium, excluding gases.   The nickel material is at least 99.995 wt% pure, excluding gas, in nickel; the vanadium material is at least 99.995 wt% pure, excluding gas, in vanadium; and nickel / vanadium 25. The method of claim 24, wherein the structure is at least 99.995% pure in nickel and vanadium, excluding gases.   25. The method of claim 24, wherein the vanadium material is at least 99.999 wt% pure, excluding gases, in vanadium.   The nickel material is at least 99.999 wt% pure, excluding gas, in nickel; the vanadium material is at least 99.999 wt% pure, excluding gas, in vanadium; and nickel / vanadium 25. The method of claim 24, wherein the structure is at least 99.999% pure, excluding gases, in nickel and vanadium.   The nickel / vanadium structure includes an average grain size greater than 40 microns throughout the structure, and the method is used to reduce the average grain size to a grain size equal to or less than 40 microns. 25. The method of claim 24, further comprising subjecting the vanadium structure to a thermomechanical processing.   32. The method of claim 31, further comprising forming a sputtered component from the structure, and the average grain size throughout the sputtered component is equal to or less than 40 microns.   The method of claim 32, wherein the sputtering component is a sputtering target.   32. The method of claim 31, wherein the thermomechanical processing results in an average grain size equal to or less than 30 microns throughout the structure.   35. The method of claim 34, further comprising forming a sputtered component from the structure, and the average grain size throughout the sputtered component is equal to or less than 30 microns.   36. The method of claim 35, wherein the sputtering component is a sputtering target.   32. The method of claim 31, wherein the thermomechanical processing results in an average grain size equal to or less than 20 microns throughout the structure.   38. The method of claim 37, further comprising forming a sputtered component from the structure, and the average grain size throughout the sputtered component is equal to or less than 20 microns.   40. The method of claim 38, wherein the sputtering component is a sputtering target.

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