Electrocodeposition of lead free tin alloys

Abstract

A method of electrocodeposition of lead free tin alloys is disclosed. The method includes the following steps: electrocodepositing tin metal and particles of a noble metal to form a composite; and converting the composite to an alloy by heating the composite.

1 . A method of electrocodeposition of lead free tin alloys, said method comprising the steps of: 
 electrocodepositing tin metal and particles of a noble metal to form a composite; and    converting said composite to an alloy by heating said composite.    
     
     
         2 . The method of  claim 1  wherein said noble metal selected from the group consisting of: 
 silver, gold, and copper.    
     
     
         3 . The method of  claim 2  wherein said heating is in a temperature range of 170° C. and 240° C.  
     
     
         4 . The method of  claim 2  wherein said heating is in a temperature range of 200° C. and 240° C.  
     
     
         5 . The method of  claim 2  wherein said composite volume percentage of said noble metal is that volume percentage wherein said composite melting temperature is in the range of the eutectic melting point.  
     
     
         6 . The method of  claim 2  wherein said composite comprising between 2.5% and 4.5% volume percentage silver.  
     
     
         7 . A method of electrocodeposition of lead free tin alloys, said method comprising the steps of: 
 electrocodepositing tin metal and silver particles to form a composite; and    converting said composite to an alloy by heating said composite.    
     
     
         8 . The method of  claim 7  wherein said heating is in a temperature range of 200° C. and 240° C.  
     
     
         9 . The method of  claim 7  wherein said composite comprising between 2.5% and 4.5% volume percentage silver.  
     
     
         10 . A method of electrocodeposition of lead free tin alloys onto a conductive substrate, said method comprising the steps of: 
 forming a mask on surface of said substrate;    electrocodepositing tin metal and particles of a noble metal to form a composite on said surface;    removing said mask; and    converting said composite to an alloy by heating said composite.    
     
     
         11 . The method of  claim 10  wherein said noble metal selected from the group consisting of: 
 silver, gold, and copper.    
     
     
         12 . The method of  claim 11  wherein said heating is in a temperature range of 170° C. and 240° C.  
     
     
         13 . The method of  claim 11  wherein said heating is in a temperature range of 200° C. and 240° C.  
     
     
         14 . The method of  claim 11  wherein said composite volume percentage of said noble metal is that volume percentage wherein said composite melting temperature is in the range of the eutectic melting point.  
     
     
         15 . The method of  claim 11  wherein said composite comprising between 2.5% and 4.5% volume percentage silver.  
     
     
         16 . A method of electrocodeposition of lead free tin alloys onto a conductive substrate, said method comprising the steps of: 
 forming a mask on surface of said substrate;    electrocodepositing tin metal and particles of silver to form a composite on said surface;    removing said mask; and    converting said composite to an alloy by heating said composite.    
     
     
         17 . The method of  claim 16  wherein said heating is in a temperature range of 200° C. and 240° C.  
     
     
         18 . The method of  claim 16  wherein said composite comprising between 2.5% and 4.5% volume percentage silver.  
     
     
         19 . A method of electrocodeposition of lead free tin alloys for protective solderable finishes, said method comprising the steps of: 
 electrocodepositing tin metal and particles of a noble metal to form a composite; and    converting said composite to an alloy by heating said composite.    
     
     
         20 . A method of electrocodeposition of lead free tin alloys for masking printed boards, said method comprising the steps of: 
 electrocodepositing tin metal and particles of a noble metal to form a composite; and    converting said composite to an alloy by heating said composite.    
     
     
         21 . A method of electrocodeposition of lead free tin alloys for controlled collapse circuit connection packaging using solder bumps, said method comprising the steps of: 
 electrocodepositing tin metal and particles of a noble metal to form a composite; and    converting said composite to an alloy by heating said composite.