Method of forming metal blanks for sputtering targets

Abstract

The present invention relates to an improvement in the manufacture of metal blanks, discs, and sputtering targets by flattening only one of the two surfaces of a metal plate. The elimination of flattening the metal plate's second surface results in a significant cost reduction. The metal plate of the present invention preferably has a single-side flatness of 0.005 inches or less, which improves the reliability of the bond between the target blank and a backing plate. Preferred metals include, but are not limited to, tantalum, niobium, titanium, and alloys thereof. The present invention also relates to machining the first side of a metal plate, bonding the first side to a backing plate, and then optionally machining the second side of the metal plate.

1 . A method for manufacturing a metal blank, said method comprising: 
 a) supplying at least one planar metal plate having a first surface and a second surface, wherein said first and said second surfaces are essentially parallel; and    b) flattening only said first surface of said metal plate whereby a metal blank is produced.    
   
   
       2 . The method of  claim 1 , wherein said metal plate comprises tantalum, copper, aluminum, titanium, niobium, cobalt, platinum, silver, gold, or alloys thereof.  
   
   
       3 . The method of  claim 1 , wherein said metal plate is tantalum.  
   
   
       4 . The method of  claim 1 , wherein said metal plate is niobium.  
   
   
       5 . The method of  claim 1 , wherein said first surface of said metal plate is flattened by machining, grinding or combinations thereof.  
   
   
       6 . A method of manufacturing a metal disc, said method comprising machining said first surface of said metal blank produced by the method of  claim 1  into a disc.  
   
   
       7 . The method of  claim 6 , wherein said metal disc comprises tantalum, copper, aluminum, titanium, niobium, cobalt, platinum, silver, gold, or alloys thereof.  
   
   
       8 . A method of manufacturing a metal disc, said method comprising machining said first surface of said metal blank produced by the method of  claim 3  into a disc.  
   
   
       9 . A method of manufacturing a metal disc, said method comprising machining said first surface of said metal blank produced by the method of  claim 4  into a disc.  
   
   
       10 . A method of forming a sputter target assembly having a metal target bonded to a backing plate comprising: 
 providing a metal sputter target which comprises a metal disc prepared by the method of  claim 6;  and    bonding a backing plate onto said metal disc.    
   
   
       11 . The method of  claim 10 , wherein said backing plate comprises copper, copper alloys, aluminum, aluminum alloys, titanium or titanium alloys or combinations thereof.  
   
   
       12 . The method of  claim 10 , wherein said metal disc is tantalum.  
   
   
       13 . The method of  claim 10 , wherein said metal disc comprises niobium.  
   
   
       14 . A method of forming a sputter target assembly having a metal target bonded to a backing plate comprising the steps of: 
 providing a metal sputter target which comprises a metal blank prepared by the method of  claim 1;  and    bonding a backing plate onto said metal blank.    
   
   
       15 . The method of  claim 14 , wherein said metal blank comprises tantalum, copper, aluminum, titanium, niobium, cobalt, platinum, silver, gold, and alloys thereof.  
   
   
       16 . The method of  claim 14 , wherein the metal blank is tantalum.  
   
   
       17 . The method of  claim 14 , wherein the metal blank is niobium.  
   
   
       18 . The method of  claim 1 , wherein said method consists essentially of machining one surface of said metal plate.  
   
   
       19 . The method of  claim 1 , wherein said second surface has a flatness of about 0.075 inches or less.  
   
   
       20 . The method of  claim 1 , wherein said second surface has a flatness of from about 0.060 inches to about 0.005 inches.  
   
   
       21 . The method of  claim 1 , wherein said second surface has a flatness of from about 0.030 inches to about 0.005 inches.  
   
   
       22 . The method of  claim 1 , wherein said first surface is machined flat to a flatness of about 0.005 inches or less.  
   
   
       23 - 33 . (canceled)  
   
   
       34 . The method of  claim 14 , wherein said metal target is bonded to said backing plate by an adhesive material, by soldering, by brazing, by diffusion bonding, by pressure fitting, by hot melting, or by explosion bonding.  
   
   
       35 . The method of  claim 1 , wherein said metal blank has a nominal thickness tolerance of at least about 5% of the rolled gauge of the plate.  
   
   
       36 . The method of  claim 1 , further comprising a diameter tolerance of about +0.025/−0.00 inches.  
   
   
       37 . A method of forming a sputter target assembly having a metal target bonded to a backing plate comprising the steps of: 
 providing a metal sputter target which comprises a metal blank prepared by the method of  claim 1;  and    bonding a backing plate onto said metal blank, wherein said metal sputter target is tantalum and said backing plate comprises copper or an alloy thereof.    
   
   
       38 . The method of  claim 10 , further comprising providing an interlayer between said metal sputter target and said backing plate prior to bonding said backing plate.  
   
   
       39 . The method of  claim 1 , wherein said first surface is machined flat to a flatness of about 0.010 inches or less.  
   
   
       40 . (canceled)