Aluminum bump bonding for fine aluminum wire

Abstract

The invention includes a packaged semiconductor device in which the bond wires are bonded to the leads with an aluminum bump bond. The semiconductor device is mounted on a leadframe having leads with a nickel plating. To form the bump bond between a fine aluminum wire, such as a 2 mil diameter wire, and the lead, an aluminum bump is bonded to the nickel plating and the wire is bonded to the bump. The bump is aluminum doped with nickel and is formed from a large diameter wire, such as a 6 mil diameter wire.

1 . A packaged semiconductor device having an aluminum bump bond comprising: 
 a bonding surface;    an aluminum bump bonded to said bonding surface, said bump comprising a length of a large diameter aluminum wire; and    an aluminum bond wire having a bond end that is bonded to said bump, said bond wire comprising a fine aluminum wire.    
     
     
         2 . The packaged semiconductor device of  claim 1 , said bonding surface comprising a nickel plating.  
     
     
         3 . The packaged semiconductor device of  claim 2 , said bump being doped with nickel.  
     
     
         4 . The packaged semiconductor device of  claim 1 , the large diameter aluminum wire having a diameter of about 6 mil.  
     
     
         5 . The packaged semiconductor device of  claim 1 , the fine aluminum wire having a diameter of about 2 mil.  
     
     
         6 . The packaged semiconductor device of  claim 1 , said bonding surface comprising a lead that is part of a leadframe.  
     
     
         7 . The packaged semiconductor device of  claim 1 , said bump having a substantially flat surface formed by a flat tip wedge tool to provide a surface for bonding the bond end of said bond wire.  
     
     
         8 . A method of packaging a semiconductor device, comprising the steps of: 
 providing a leadframe with a semiconductor device attached thereto, the leadframe having a plurality of leads;    building a bump on the surface of one or more of the leads; and    wire bonding an aluminum bond wire to each of the bumps.    
     
     
         9 . The method of  claim 8 , the bond wire having a fine diameter.  
     
     
         10 . The method of  claim 9 , the bond wire having a diameter of about 2 mil.  
     
     
         11 . The method of  claim 8 , the bump building step comprising bonding a portion of a large-diameter aluminum wire to one or more of the leads; and breaking the large-diameter wire away from the portion to leave a bump.  
     
     
         12 . The method of  claim 11 , the step of bonding a portion of a large-diameter aluminum wire comprising the use of a flat tip wedge tool.  
     
     
         13 . The method of  claim 11 , the bump having a diameter of about 6 mil.  
     
     
         14 . The method of  claim 8 , the bump comprising aluminum.  
     
     
         15 . The method of  claim 14 , the leads having a nickel plating and the bump being doped with nickel.  
     
     
         16 . The method of  claim 8 , further comprising the step of encapsulating the leadframe, semiconductor device, and bond wires in a non-conducting encapsulation polymer.