SPUTTERING TARGETS AND METHODS OF FORMING THE SAME
In various embodiments, sputtering targets incorporate an intermediate plate having a coefficient of thermal expansion (CTE) between a CTE of the backing plate and a CTE of the target material.
1 . A method of forming a sputtering target, the method comprising:
providing an intermediate plate on a backing plate; and
forming a target material on the intermediate plate,
wherein the intermediate plate has a coefficient of thermal expansion (CTE) between a CTE of the backing plate and a CTE of the target material.
2 . The method of claim 1 , wherein the intermediate plate is formed on the backing plate by spray deposition.
3 . The method of claim 2 , wherein the intermediate plate is formed on the backing plate by cold spray.
4 . The method of claim 1 , wherein the target material is formed on the intermediate plate by spray deposition.
5 . The method of claim 4 , wherein the target material is formed on the intermediate plate by cold spray.
6 . The method of claim 1 , wherein providing the intermediate plate comprises bonding the intermediate plate to the backing plate.
7 . The method of claim 6 , wherein the target material is formed on the intermediate plate prior to the intermediate plate being bonded to the backing plate.
8 . The method of claim 7 , wherein the target material is formed by spray deposition.
9 . The method of claim 8 , wherein the target material is formed by cold spray.
10 . The method of claim 1 , wherein a top surface of the intermediate plate has a profiled surface contour comprising one or more recesses corresponding to regions of high target-material consumption during a physical-vapor-deposition process.
11 . The method of claim 1 , wherein the intermediate plate substantially prevents warpage of the backing plate due to residual stress in the target material.
12 . A sputtering target comprising:
a backing plate comprising a backing-plate material;
a target material disposed over the backing plate, a melting point of the target material exceeding a melting point of the backing plate by at least 500° C.; and
an intermediate plate disposed between the backing plate and the target material, the intermediate plate having a coefficient of thermal expansion (CTE) between a CTE of the backing plate and a CTE of the target material.
13 . The sputtering target of claim 12 , wherein the target material consists essentially of unmelted metal powder.
14 . The sputtering target of claim 12 , wherein the intermediate plate consists essentially of unmelted metal powder.
15 . The sputtering target of claim 12 , wherein the target material is at least one member of the group consisting of: niobium, tantalum, tungsten, molybdenum, zirconium, titanium, and alloys thereof.
16 . The sputtering target of claim 12 , wherein the intermediate plate comprises an alloy of the backing-plate material and the target material.
17 . The sputtering target of claim 12 , wherein the target material has a substantially random crystalline texture.
18 . The sputtering target of claim 12 , wherein the backing-plate material comprises (i) copper, (ii) aluminum, or (iii) an alloy of beryllium with at least one of copper or aluminum.
19 . The sputtering target of claim 12 , wherein the target material is substantially free of grain-size banding and texture banding.
20 . The sputtering target of claim 12 , wherein the target material has a substantially uniform equiaxed grain structure and an average grain size less than 44 microns.
21 . The sputtering target of claim 12 , wherein a top surface of the intermediate plate has a profiled surface contour comprising one or more recesses corresponding to regions of high target-material consumption during a physical-vapor-deposition process.