A solder paste comprising a powder of a Zn-containing Sn-based, lead-free solder
mixed with an activator-containing rosin-based flux to which 0.5-10.0 wt % of isocyanuric
acid or a haloalkyl ester thereof is added can prevent the formation of solder
balls and voids during reflow soldering and exhibit good solderability. A solder
paste comprising a powder of an Ag- or Zn-containing Sn-based, lead-free solder
mixed with an activator-containing rosin-based flux to which 0.01-10.0 wt % of
a salicylamide compound also does not exhibit a change in viscosity and exhibits
good solderability.
