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50 SMT Magazine • February 2015 The elimination of lead in electronic equip- ment due to governmental regulations (Euro- pean Union End of Life Vehicle Directive and European Union Restriction of Hazardous Sub- stances Directive) has increased the risk of elec- trical shorting due to the formation of tin whis- kers in electronic products. Tin whiskers are hair-like tin structures that grow sporadically on surfaces coated with tin. Whiskers are often dif- ficult to detect due to their small cross-sectional dimensions, typically ranging between 1 and 5 micrometers, which may be 10 to 50 times finer than a human hair. While their cross-section- al dimensions are small, whiskers can grow to lengths greater than a millimeter. Such lengths are sufficient to bridge the distance between tightly spaced electronic parts. Despite the dif- ficulty of detecting them, tin whiskers have been identified as a cause of failure in medical, aerospace, power, and automotive equipment. In particular, control systems, such those found in automotive applications, have been found to have significant tin whisker failure risks [1] . Further, coupled with the increased use of tin as a surface finish in electronics, the continued trend towards higher interconnect densities and compact electronics is expected to increase the failure risk presented by the formation of tin whiskers. With the use of tin-based solder materials for creating electrical connections, tin is used extensively in electronics. With regards to by Michael Osterman univerSiTY OF MArYlAnD Tin Whiskers Remain a Concern Feature

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