AEM Inc – Tin Whisker Mitigation



Tin Whisker Mitigation (TWM) by adding lead (Pb) to chip size components with pure tin (Sn) terminals.  Our Sn-Pb conversion process involves both Sn-Pb plating and subsequent fusion processing to ensure that the resultant component terminations are a homogenous mixture of Sn-Pb.  The AEM Sn-Pb conversion process is NOT a hot solder dip operation that introduces the risk of thermal shock to the components.

AEM Inc.’s tin / lead components are classified EAR99 under the jurisdiction of the U.S. Department of Commerce.  EAR99 items are eligible for export to most end users as NLR (No License Required); however, there are certain countries and end users for which a license will be required as referenced in EAR part 736. Additionally, a license may be required if the item will be used in the design, development, production, or use in nuclear, chemical, or biological weapons, or ballistic missiles.

Issues Facing Hi-Rel Product Manufacturers:

  • Components with solder terminals comprised of >3% lead are not prone to tin whisker problems.
  • Whiskers tend to grow unpredictably on 100% tin surfaces.
  • There is no accepted accelerated method to test for the propensity of tin whisker growth.
  • Components with 100% tin external radial-leaded components can be tin / lead hot solder dipped, although this is not always 100% effective.
  • 100% tin terminated chip size style components should not be tin / lead hot solder dipped due to thermal shock concerns.

Exclusive AEM Sn/Pb Conversion Process Has Been Qualified by Major Aerospace OEMs:

  • The AEM tin / lead conversion process is effective for most chip size passive components including capacitors, inductors, resistors, ferrite chip beads, fuses, resistor arrays, capacitor arrays, bead arrays, and many molded body passive and active surface mount component types.
  • Tin / lead processed components are subjected to 100% visual and mechanical inspections per applicable EIA guidelines (including sample solderability, leach resistance, terminal strength and DPA screening).
  • Optional component up-screening and QCI also performed by AEM’s MIL-STD-202 lab.
  • Tin / lead converted and up-screened components will be warranted as AEM products.
  • AEM’s tin / lead conversion process is applicable to most multi-layer chip style components. Other components may be processed subject to an AEM pre-evaluation and component construction analysis (generally performed by AEM at no cost to customer).