What are tin whiskers?
Tin-whiskers are a crystalline metallurgical phenomenon where single crystal metallic tin-filaments spontaneously grow out of electroplated tin films on various metal substrates. It is generally agreed that whisker formation and growth is influenced by: 1.) Localized stress – for copper-based leadframes, believed to be driven by non-uniform tin-copper intermetallic formation at the lead frame to tin interfaces 2.) Global stress, resultant from external mechanical stress 3.) The purity of the tin plate 4.) The microstructure of the tin plate 5.) The metal surface (leadframe) on which it is plated 6.) The way the leadframe is formed 7.) The plating thickness 8.) Post plate processing. Tin whiskers can cause short circuits in electronic and electrical equipment and have been shown to be responsible for intermittent and catastrophic failure of electronic systems.
