| |
SIX SIGMA is the industry leader
in hot solder dipping of components. This method is used to change the termination
finish of components from leaded to lead-free or vice versa. It is currently
one of the strategies being used to mitigate tin whiskers, which can form when
pure tin plating is used. Hot solder dipping of pure tin-finished terminations
using tin-lead (Sn-Pb) solder, reduces tin whisker formation by replacing tin
with a tin-lead alloy. It is very important that no pure tin remains on the
components. Hot solder dipping of tin-finished leads with lead-free alloys such
as tin-silver-copper (SAC) also reduces whisker formation. Although not as effective
as lead, so far, there is no evidence that these SAC alloys produce whiskers.
Hot solder dip applies to almost
all types of packages, except BGAs and CGAs. There are several reasons why components
are solder dipped. The method is used to change the lead finish, i.e., from
lead-free to leaded, or from leaded to lead-free. It is also used to improve/restore
the solderability of the parts, and can act as the primary finish for the terminations.
|
|
|
|
