A whisker is a thin conductive filament, usually tin and sometimes zinc, that grows out of a plated surface over months or years, driven by internal stress in the coating. Whiskers can reach millimetres in length, bridging fine-pitch leads or breaking off and landing elsewhere. Pure tin finishes on leads and boards raise the risk, so high-reliability users require tin-lead, nickel underplate, annealed matte tin or conformal coating as mitigation.
Field return has a whisker bridging two leads on the bright tin connector, find out if the supplier changed plating.
Also heard as
- tin whisker
Related terms
Surface finish
Final coating on exposed copper pads that stops them oxidising and decides how well they solder.
Bridging
Solder defect in which solder joins two pads or leads that should be separate, creating a short.
CAF
Conductive anodic filament: copper growth along glass fibers inside a board that shorts holes under voltage.