Sptutter targets and methods of manufacturing same to reduce particulate emission during sputtering

Abstract

Methods for reducing inclusion content of sputter targets and targets so produced are disclosed. Inclusions ( 93 ) may be reduced by adding a small amount of Si to the molten Al or molten Al alloy followed by filtering of the molten metals through a filter medium ( 175 ). Targets having substantially no inclusions ( 93 ) therein of greater than about 400 μm are especially useful in the sputtering of large flat panel displays and result, upon sputtering, in a reduction in the amount of macrmparticles sputtered onto the substrate.

What is claimed is:  
     
         1 . A method of making an aluminum or aluminum alloy sputter target adapted for sputtering of a flat panel display comprising providing molten Al or Al alloy, adding to said molten Al or Al alloy an amount of between about 0.01-2.00 wt % Si to form a molten alloy mixture, forwarding said molten alloy mixture through a filter element to remove inclusions therefrom, and allowing said filtered alloy mixture to solidify.  
     
     
         2 . Method as recited in  claim 1  wherein said filter element is a sintered ceramic filter.  
     
     
         3 . Method as recited in  claim 2  wherein said filter element is a sintered alumina having a grit size of about 2 to about 14.  
     
     
         4 . Method as recited in  claim 3  wherein said filter element has a grit size of about 8.  
     
     
         5 . Method as recited in  claim 1  wherein said Cu is present in said molten alloy in an amount of about 0.01 to 3.00%.  
     
     
         6 . Method as recited in  claim 1  wherein said molten alloy mixture is Al 0.5 Cu 0.5 Si.  
     
     
         7 . Method as recited in  claim 6  wherein after said forwarding of said molten alloy mixture through said filter element said mixture is substantially free of inclusions of the size of about 400 μm or greater therein.  
     
     
         8 . In a method of sputter coating a flat panel display from an Al or Al alloy target, the improvement comprising providing a target that is substantially fee of macroparticles of the size of 400 μm or greater therein.  
     
     
         9 . A method as recited in  claim 8  wherein said Al target comprises an amount of Si therein present in an amount of about 0.01-2.00 wt %.  
     
     
         10 . A method as recited in  claim 9  wherein said Al target further comprises an amount of Cu therein present in an amount of about 0.01 to 3.00 wt %.  
     
     
         11 . A method as recited in  claim 10  wherein said target is Al 0.5 Si 0.5 Cu.  
     
     
         12 . Sputter target comprising Al or Al alloy sputter material, said target having a sputter track area adapted for increased consumption of said sputter material therein, said sputter track being substantially free of inclusions of the size of 400 μm and greater.  
     
     
         13 . Sputter target as recited in  claim 12  comprising Cu present in an amount of about 0.01-3.00 wt %.  
     
     
         14 . Sputter target as recited in  claim 13  further comprising Si present in an amount of 0.01 to 2.0 wt %.  
     
     
         15 . Sputter target as recited in  claim 14  wherein said target is Al 0.5 Cu 0.5 Si.  
     
     
         16 . Sputter target comprising a face area of target material to be sputtered onto a desired substrate, said target material being substantially free of inclusions in said target material of the size of 800 μm and greater.  
     
     
         17 . Sputter target as recited in  claim 16  wherein said target material includes a sputter track having a sputter track area adapted for increased consumption of said target material thereat during sputtering, said sputter track being substantially free of inclusions therein of the size of 400 μm and greater.  
     
     
         18 . Sputter target being substantially free of inclusions of the size of 400 μm and greater.  
     
     
         19 . In a cathodic sputter coating system of the type having a cathode and an anode, a sputter target operatively associated with said cathode and a flat panel display substrate proximate said anode for coating of said substrate by material dislodged from said target, said system operating at a power density of about 16 W/cm 2  and greater, the improved method comprising sputtering a target comprising a metal or metal alloy in said system, said target being substantially free of inclusion defects on the size of 800 μm and greater therein.  
     
     
         20 . Method as recited in  claim 19  wherein said target is Al or Al alloy.  
     
     
         21 . Method as recited in  claim 20  wherein said target further comprises Cu therein, present in an amount of about 0.01-3.00 wt %.  
     
     
         22 . Method as recited in  claim 20  wherein said target further comprises Si therein, present in an amount of about 0.01-2.00 wt %  
     
     
         23 . Method as recited in  claim 22  wherein said target is Al 0.5 Cu 0.5 Si.  
     
     
         24 . Method as recited in  claim 19  wherein said target is substantially free of inclusion defects therein on the size of 400 μm and greater.