Since the electronics industry moved to lead-free solders, which typically have a tin content of more than 95 percent, there has been concern about the possibility of circuit malfunctions due to Sn whisker growth. That concern has been mitigated to some extent by the greater understanding of the factors that affect whisker growth, which resulted from the intensive study of the phenomenon which has occurred in recent years. With this knowledge, it has been possible to take some measures to reduce the likelihood of whisker growth, but not all of the situations encountered in commercial production have been investigated.
It is now generally accepted that whisker growth is a response to compressive stress within the tin crystal, and the challenge is to eliminate or minimize the factors that can generate such a stress. Corrosion processes have been identified as one source of that stress. Temperature and humidity have an effect on the amount of corrosion and thus the incidence of whiskers on printed circuit boards soldered with Sn-3.0Ag-0.5Cu alloy using wave, reflow and hand soldering methods with typical “no-clean” fluxes.
Following the very successful 2005 and 2006 International Conferences on Lead-free Soldering, the SMTA International Conference on Soldering and Reliability held annually in Toronto since 2007 brings together the community of soldering and reliability experts.
For more information, please visit http://www.smta.org/education/symposia/symposia.cfm#toronto.
The SMTA membership is an international network of professionals who build skills, share practical experience and develop solutions in electronic assembly technologies, including microsystems, emerging technologies, and related business operations.
Nihon Superior was founded in 1966 when it began marketing unique flux products imported from the US. The company made its mark on society by gathering the most advanced soldering and brazing technologies and products from around the world, and supplying them to companies in the metal-joining industry. A turning point for the company came when it started developing its own soldering materials and with the success of its unique SN100C lead-free solder alloy Nihon Superior has become a major player in the global market. To support the growing demand for its products Nihon Superior has established manufacturing and sales centers in Japan, China and other Asian countries and formed business partnerships with companies in other markets.