It's been nearly a decade since the European Union passed the Restriction of Hazardous Substances Directive (RoHS), but the electronics industry is still grappling with the transition to lead-free systems. High-reliability fields like aerospace and military still have a number of issues that haven't been resolved.
Some of these high-reliability markets are currently excluded from RoHS regulations, but many companies are finding it difficult to buy tin-lead components from chipmakers who can't justify making small numbers of parts with lead-based finishes. There are still many knowledge gaps regarding the long-term performance of lead-free assemblies in demanding applications.
A white paper written by the IPC Pb-free Electronics Risk Management (PERM) Council, IPC-WP-012, Pb-free Electronics Risk Management (PERM) Council Pb-free Research Priorities, explores several priority research areas to help close the knowledge gaps regarding the impact and risks associated with the implementation of a range of lead-free materials.
Members of the PERM Council determined that there are four key problem areas: Tin whisker failure modes and risk mitigation, complex systems logistics, and issues surrounding lead-free interconnections (e.g., solder joints) that include reliability models, and assembly qualification. These research areas are common across five product platforms: avionics, ground-based systems, missiles and aviation systems, space systems, and submarine-sea systems. PERM members believe that improvements in those areas will avail other fields.
The benefits of this research could be significant. The research would allow design engineers and manufacturing teams to understand the risk associated with issues that impact the reliability of electronics assemblies that use lead-free components and solders. The applied knowledge from the research would substantially reduce penalty costs associated with field failures of electronic systems. The significance of failures from tin-whisker induced electrical shorts or from mechanical fracture of electrical connections manufactured with lead-free components and materials are especially detrimental. These types of failures are intermittent and not predictable, which is very undesirable in high-reliability electronic systems.
