Tin alloy solder compositions

Abstract

A lead-free and bismuth-free solder alloy composition for electronic assembly applications having reduced toxicity. The alloy composition comprises about 0.01% to about 4.5% silver; about 0.01% to about 3% copper; about 0.002% to about 5.0% antimony; about 85% to about 99% tin and about 0.002% to about 1% of either nickel or cobalt. The alloy composition has a melting temperature of about 217° C., with superior wetting and mechanical strength making the alloy composition well suited for electronic circuit board manufacture and lead less component bumping or column arrays, and replacement of conventional tin-lead solders.

1 . A lead-free, bismuth-free solder alloy composition comprising about 0.01% to about 4.5% silver; about 0.01% to about 3% copper; about 0.002% to about 5.0% antimony; about 0.002% to about 1% nickel; and about 85% to about 99% tin.  
     
     
         2 . A lead-free bismuth-free solder alloy composition comprising about 1.75% to about 2.0% silver; about 0.05% to about 0.09% copper; about 0.02% to about 2% antimony; about 0.008% to about 1.5% nickel; and about 94.4% to about 98.2% tin.  
     
     
         3 . A lead-free, bismuth-free solder alloy composition comprising about 1.75% to about 2.0% silver; about 0.8% copper; about 0.5% antimony; about 0.08% nickel; and about 96.6% to about 96.9% tin.  
     
     
         4 . A lead-free bismuth-free solder alloy composition comprising about 0.5% to about 1.75% silver; about 0% to about 0.5% copper; about 0.002% to about 0.2% antimony; about 0.08% to about 0.04% nickel; and about 97.5% to about 99.4% tin.  
     
     
         5 . A lead-free, bismuth-free solder alloy composition comprising about 0.01% to about 4.5% silver; about 0.01% to about 3% copper; about 0.002% to about 5.0% antimony; about 0.002% to about 1% cobalt; and about 85% to about 99% tin.  
     
     
         6 . A lead-free, bismuth-free solder alloy composition comprising about 1.0% to about 1.75% silver; about 0.2% to about .99% copper; about 0.0001% to about 2.0% antimony; about 0.0002% to about 1% cobalt; and about 94.3% to about 98.8% tin.  
     
     
         7 . A lead-free bismuth-free solder alloy composition comprising about 1.0% to about 1.75% silver; about 0.8% copper; about 1.0% antimony; about 0.008% cobalt; and about 96.44% to about 97.2% tin.  
     
     
         8 . A lead-free bismuth-free solder alloy composition comprising about 0.02% to about 1.0% silver; about 0.2% to about 0.8% copper; about 0.2% to about 0.8% antimony, about 0.008% to about 0.4% cobalt, and about 97% to about 99.6% tin.  
     
     
         9 . A lead less component bumping or column array comprising the alloy composition of any one of claims  1 - 2  and  5 - 6 .  
     
     
         10 . An electronic assembly comprising the alloy composition of any one of claims  1 - 2  and  5 - 6 .  
     
     
         11 . The alloy composition of  claim 1  or  5 , wherein a flux core is inserted into the composition to form an electronic assembly flux cored wire solder.  
     
     
         12 . The alloy composition of  claim 1  or  5 , wherein the composition constitutes a fluxed core of flux and the alloy particles.  
     
     
         13 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder bar; said solder bar being used in electronic assembly solder machines.  
     
     
         14 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder ingot, said solder ingot being used in electronic assembly.  
     
     
         15 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder wire, said solder wire being used in electronic assembly.  
     
     
         16 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder chip, said solder chip being used in electronic assembly.  
     
     
         17 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed Into a solder ribbon, said solder ribbon being used in electronic assembly.  
     
     
         18 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder powder, said solder powder being used in electronic assembly.  
     
     
         19 . The alloy composition of  claim 1  or  5 , wherein said alloy composition is formed into a solder preform, said solder preform being used in electronic assembly.  
     
     
         20 . The alloy composition of  claim 1  or  5 , wherein said alloy is employed in hot air levelling of printed circuit boards.  
     
     
         21 . The alloy composition of  claim 1  or  5 , wherein said alloy is employed in assembling surface mounted printed circuit boards.  
     
     
         22 . The alloy composition of  claim 1  or  5 , wherein said alloy is employed in the solder coating of printed circuit boards.  
     
     
         23 . The alloy composition of  claim 1  or  5 , wherein said alloy is employed in roll tinning of circuit boards.  
     
     
         24 . The alloy composition of  claim 1  or  5 , wherein said alloy is employed in surface mount assembly of electronic components onto a printed circuit board.  
     
     
         25 . The alloy composition of  claim 19 , wherein said solder preform is fluxed.  
     
     
         26 . The alloy composition of  claim 19 , wherein said solder preform is unfluxed.