Description:
Project ID: D2018-36
Background
Metal whiskering is a problem with electrical devices in which the metal, such as tin, suffer from compressive stress or high work functions and grow hair-like structure that extend from the metal. This causes circuit shorts and electrical failures. Current solutions require the use of lead or conformal coatings to mitigate whisker formation. Conformal coatings are insulating and unreliable. The use of lead is now restricted by directives, namely the Restriction of Hazardous Substances, and is banned in consumer electronics in the European Union. Therefore, there is a need for a whisker mitigation solution that does not require hazardous materials.
Invention Description
Researchers have developed an alternative way to mitigate whiskers. In a year-long study, the addition of a NiO layer between the copper and tin layers resulted in no whisker formation.
Applications
• Printed circuit boards for a variety of industries
Advantages
• Can be used with current manufacturing methods
• NiO is relatively inexpensive, effective layer ~100nm thick (or less)
• Deposition could include dip coating, sputtering, and sol-gel.
• Does not require lead
• Longer studies may prove this to prevent whiskers entirely
IP Status: Patent Pending
Publication: V. Borra, S. Itapu, and D. Georgiev, “Sn whisker mitigation using a NiO underlying layer”, Journal of Physics D: Applied Physics, 2017 (50, 475309).