Method for making composite sputtering targets and the tartets made in accordance with the method

Abstract

Composite sputtering targets are made by hot pressing metal or metal containing powders into a backing plate which can be comprised of a different material with a depression formed in a surface or can be a used sputtering target of the same or different material. The depression corresponds to the erosion pattern of a target having the same geometry. The depression can be formed for example, by machining. The backing plate is loaded into a graphite die and covered with the sputtering material to form an assembly. A ram is added and the assembly with the ram is loaded into a hot press which is taken to an appropriate pressure and temperature under vacuum to form a composite sputtering target having a sputtering zone of densified sputtering material.

1 . A method of manufacturing composite sputtering targets comprising the steps of:
 (a) providing a backing plate having a geometry and a surface which includes a depression,   (b) placing the backing plate into a graphite die designed to accommodate a geometry of the backing plate,   (c) adding a sputtering material to the graphite die on top of the backing plate to from a die assembly   (d) placing a graphite die ram into the die assembly so that the ram contacts the sputtering material,   (e) placing the die assembly and ram into an hydraulic press and pressing the graphite die ram into graphite die to a specific pressure,   (e) placing the compacted die assembly and ram into a vacuum hot press furnace chamber and contacting the die ram with the hydraulic ram of the hot press,   (g) sealing and evacuating the vacuum hot press furnace chamber to a vacuum level of between about 200 and 50 mTorr,   (h) heating the vacuum hot press furnace chamber and contents to a pre-determined temperature and applying pressure to the graphite die ram via the hydraulic press ram,   (i) lowering the pressure on the ram, and cooling and raising the vacuum level of the hot press vacuum furnace chamber, and   (j) removing the die assembly and ram from the vacuum hot press furnace.   
     
     
         2 . The method of  claim 1  further including the step of removing a composite sputtering target pre-form from the graphite die. 
     
     
         3 . The method of  claim 2  including the further step of machining the surface of the composite sputtering target pre-form. 
     
     
         4 . The method of  claim 3  wherein the machining step includes one or more of diamond grinding and electrodynamic machining. 
     
     
         5 . The method of  claim 1 , wherein the backing plate comprises a material that is a refractory metal or alloy that is mechanically and chemically compatible with the sputtering material. 
     
     
         6 . The method of  claim 5  wherein the backing plate material comprises is Mo, Ta, or Nb. 
     
     
         7 . The method of  claim 1 , wherein said sputtering material is comprises pure Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals, or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals and oxides or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt with oxides. 
     
     
         8 . The method of  claim 1 , wherein the sputtering material is comprised of precious metals or precious metal alloys or mixtures with other metals or metal alloys or metal oxides. 
     
     
         9 . The method of  claim 1 , wherein the composite sputtering target geometry is circular, rectangular, delta, or oval shaped. 
     
     
         10 . The method of  claim 1 , wherein the composite sputtering target is comprised of more than one section requiring a multi-tile sputtering target design. 
     
     
         11 . The method of  claim 1 , including the further step of forming the depression in the backing plate. 
     
     
         12 . The method of  claim 11  including the further step of calculating the erosion pattern of a used sputtering target having a geometry which corresponds to the geometry of the composite sputtering target, using that erosion pattern to calculate an optimal shape for the depression, and forming the depression to correspond to the optimal shape in a surface of the backing plate by machining the backing plate. 
     
     
         13 . The method of  claim 1  in which the backing plate is a used sputtering target. 
     
     
         14 . The method of  claim 1  in which the backing plate is comprised of a material which is different than the sputtering material. 
     
     
         15 . The method of  claim 1 , wherein a barrier material is used, and the material of the barrier material is inserted between the sputtering material and backing plate so as to prevent adverse reactions between the precious metal containing material and the machined backing plate material. 
     
     
         16 . The method of  claim 15 , wherein the barrier material is comprised of one or more of Nb, Ta, Mo of one of more of a foil, a powder or a coating. 
     
     
         17 . A method of manufacturing composite sputtering target including a sputtering material comprising the steps of:
 (a) selecting a backing plate material that is chemically and mechanically compatible with the sputtering material,   (b) forming a groove in the backing plate material that approximates the erosion groove of a spent sputtering target to form a backing plate having a geometry including a top surface,   (c) placing the backing plate into a graphite hot press die designed to accommodate the geometry of the backing plate,   (d) adding a predetermined amount of powder of the sputtering material onto the top surface of the backing plate so as to as to fill the groove and cover the top surface of the backing plate to form a graphite die backing plate assembly,   (e) vibrating the graphite die backing plate assembly so as to evenly distribute the sputtering material powder over the top surface of the backing plate and thus form a top surface of the sputtering material powder,   (f) placing a graphite die ram having a top surface and bottom surface into the graphite die so that the bottom surface of the ram contacts the top surface of the sputtering material powder to form an assemblage of the graphite die backing plate assembly and the graphite die ram,   (g) placing the assemblage into an hydraulic press and pressing the graphite die ram to a predetermined pressure so as to compact the sputtering material powder into the backing plate groove and unto the surface of the machined backing plate to from a compacted assemblage,   (h) placing the compacted assemblage into a vacuum hot press furnace chamber and lowering the hydraulic ram of the hot press onto the graphite die ram so as to contact the top surface of the die ram,   (i) sealing and evacuating the vacuum hot press furnace chamber to a vacuum level of between about 200 and about 50 mTorr,   (j) heating the vacuum hot press furnace chamber and contents to a pre-determined temperature suitable for the densification of the sputtering material powder into a solid, dense form,   (k) applying pressure to the graphite die ram via the hydraulic press ram to a pre-determined pressure suitable for the densification of the sputtering material powder into a solid, dense form,   (l) holding the assemblage at the applied temperature and pressure for a pre-determined amount of time suitable for the densification of the sputtering material powder into a solid, dense form to form a sputtering target pre-form,   (m) releasing the pressure on the hydraulic press ram, and cooling and releasing the vacuum level of the hot press vacuum furnace chamber,   (n) removing the assemblage from the vacuum hot press furnace and removing the composite sputtering target pre-form from the graphite die,   (o) finishing the surface of the composite sputtering target pre-form to obtain a composite sputtering target.   
     
     
         18 . The method of  claim 17 , wherein the backing plate comprises a material that is a refractory metal or alloy that is mechanically and chemically compatible with the sputtering material. 
     
     
         19 . The method of  claim 18  wherein the backing plate material comprises is Mo, Ta, or Nb. 
     
     
         20 . The method of  claim 17 , wherein said sputtering material is composed of pure Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals and oxides or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt with oxides such as TiO 2 . 
     
     
         21 . The method of  claim 17 , wherein the sputtering material is composed of precious metals or precious metal alloys. 
     
     
         22 . The method of  claim 21  wherein the sputtering material is Ag or Au or mixtures of Ag or Au with other metals or metal alloys or metal oxides. 
     
     
         23 . The method of  claim 17 , wherein the composite sputtering target has a geometry which is circular, rectangular, or delta shaped. 
     
     
         24 . The method of  claim 17 , wherein the composite sputtering target is composed of more than one section requiring a multi-tile sputtering target design. 
     
     
         25 . The method of  claim 17 , wherein a spent composite sputtering target is used as the backing plate to produce the composite sputtering target. 
     
     
         26 . The method of  claim 17 , wherein a spent composite sputtering target is used a plurality of times as the backing plate to produce the composite sputtering target. 
     
     
         27 . The method of  claim 17 , wherein a barrier material or other material chemically and mechanically compatible with the sputtering material and the backing plate material is inserted between the precious metal containing material and the machined backing plate. 
     
     
         28 . The method of  claim 27 , wherein the barrier material is inserted between the sputtering material and the backing plate material by the use of foils, powders or coatings composed of the barrier material. 
     
     
         29 . A method of increasing the production efficiency of a sputtering material comprising the steps of:
 forming a sputtering target perform by   (a) providing a backing plate having a geometry which includes a surface which provides a depression,   (b) placing the backing plate into a graphite die designed to accommodate the geometry of the backing plate,   (c) adding a sputtering material to the graphite die on top of the backing plate to from a die assembly   (d) placing a graphite die ram into the die assembly so that the ram contacts the sputtering material,   (e) placing the die assembly and ram into an hydraulic press and pressing the graphite die ram into the graphite die to a specific pressure to form a compacted die assembly,   (f) placing the compacted die assembly and ram into a vacuum hot press furnace chamber and contacting the die ram with the hydraulic ram of the hot press,   (g) sealing and evacuating the vacuum hot press furnace chamber to a vacuum level of between about 200 and 50 mTorr,   (h) heating the vacuum hot press furnace chamber and contents to a pre-determined temperature and applying pressure to the graphite die ram via the hydraulic press ram,   (i) lowering the pressure on the hydraulic press ram and cooling and releasing the vacuum level of the hot press vacuum furnace chamber,   (j) removing the compacted die assembly and ram from the vacuum hot press furnace,   (k) removing a composite sputtering target pre-form from the graphite die to form a composite sputtering target,   
       using the composite sputtering target for a sputtering process to form a used composite sputtering target; and
 using the used composite sputtering target as a backing plate to form a new composite sputtering target. 
 
     
     
         30 . The method of  claim 29  including the further step of machining the surface of the composite sputtering target pre-form to obtain specified physical dimensions of the composite sputtering target. 
     
     
         31 . The method of  claim 30  wherein the machining step includes one or more of diamond grinding and electrodynamic machining. 
     
     
         32 . The method of  claim 30 , wherein the backing plate comprises a material that is the sputtering material or Mo, Ta, or Nb. 
     
     
         33 . The method of  claim 30 , wherein said sputtering material is composed of pure Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals, or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals, and oxides such as TiO 2  or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt with oxides. 
     
     
         34 . A composite sputtering target comprised of a backing plate which is one or more of Mo, Ta, and Nb, and a sputtering zone which is composed of pure Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals, or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt, with transition metals and oxides or mixtures of Ru, Rh, Pd, Re, Os, Ir, Pt with oxides, the sputtering zone being a densified area of sputtering material chemically, thermally and electrically consolidated with the backing target, and the sputtering target having a suitable geometry for use in a sputtering process. 
     
     
         35 . The composite sputtering target of  claim 34 , wherein a barrier material comprised of Nb, Ta, Mo, is inserted between the sputtering material and backing plate so as to prevent adverse reactions between the precious metal containing material and the machined backing plate material. 
     
     
         36 . The composite sputtering target of  claim 34  wherein the configuration of the sputtering zone is formed by calculating the erosion pattern of a used sputtering target having a geometry which corresponds to the geometry of the composite sputtering target and using that erosion pattern to calculate the sputtering zone.