Solder alloy

Abstract

An alloy suitable for use in a wave solder process, hot air levelling process, a ball grid array or chip scale package comprising no more than 3 wt.% bismuth, from 0.15-1.5 wt.% copper, from 0.1-1.5 wt.% silver, and the balance tin, with optionally other alloying elements in certain embodiments, together with unavoidable impurities.

1 . An alloy suitable for use in a wave solder process, hot air levelling process, a ball grid array or chip scale package, the alloy comprising
 bismuth in a content that does not exceed 3 wt %,   from 0.15-1.5 wt. % copper,   from 0.1-1.5 wt. % silver,   from 0-0.1 wt. % phosphorus,   from 0-0.1 wt. % germanium,   from 0-0.1 wt. % gallium,   from 0-0.3wt. % of one or more rare earth elements,   from 0-0.3 wt. % indium,   from 0-0.3 wt. % magnesium,   from 0-0.3 wt. % calcium,   from 0-0.3 wt. % silicon,   from 0-0.3 wt. % aluminium,   from 0-0.3 wt. % zinc,   and at least one of the following elements   from 0.02-0.3 wt % nickel,   from 0.008-0.2 wt % manganese,   from 0.01-0.3 wt % cobalt,   from 0.01-0.3 wt % chromium,   from 0.02-0.3 wt % iron, and   from 0.008-0.1 wt % zirconium, and the balance tin, together with unavoidable impurities.   
     
     
         2 . The alloy as claimed in  claim 1  comprising from 0.08 to 1 wt. % Bi. 
     
     
         3 . The alloy as claimed in  claim 2  comprising from 0.08 to 0.5 wt. % Bi. 
     
     
         4 . The alloy as claimed in  claim 3  comprising from 0.08 to 0.2 wt. % Bi. 
     
     
         5 . The alloy as claimed in  claim 2  comprising from 0.15 to 1 wt. % Cu. 
     
     
         6 . The alloy as claimed in  claim 5  comprising from 0.5 to 0.9 wt. % Cu. 
     
     
         7 . The alloy as claimed in  claim 6  comprising from 0.6 to 0.8 wt. % Cu. 
     
     
         8 . The alloy as claimed in  claim 2  comprising from 0.1 to 1 wt. % Ag. 
     
     
         9 . The alloy as claimed in  claim 8  comprising from 0.1 to 0.5 wt. % Ag. 
     
     
         10 . The alloy as claimed in  claim 9  comprising from 0.2 to 0.4 wt. % Ag. 
     
     
         11 . The alloy as claimed in  claim 5  comprising from 0.1 to 1 wt. % Ag. 
     
     
         12 . The alloy as claimed in  claim 11  comprising from 0.1 to 0.5 wt. % Ag. 
     
     
         13 . The alloy as claimed in  claim 12  comprising from 0.2 to 0.4 wt. % Ag.