Microelectronic Component Specialist

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Robotic Hot Solder Dip


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. 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.



Applicable Specifications & Standards:

MIL-PRF-38535, General Specification for Integrated Circuits Manufacturing
MIL-PRF-38534, General Specification for Hybrid Microcircuits
MIL-PRF-19500, General Specification for Semiconductor Devices
IPC/EIA J-STD-001, Requirements for Soldered Electrical and Electronic Assemblies
SIX SIGMA SM-4030, Baseline Requirements for Hot Solder Dip

More about Tin Whiskers:

SIX SIGMA’s white paper on Tin Whiskers (PDF)
NASA - Tin Whiskers: A History of Documented Failures (External)
NASA’s information on Tin Whiskers (External)