Surface Finishes In A Lead-free World

摘要

Purpose - The aim of this paper is to detail the changes needed to ensure compatibility of printed-circuit board (PCB) surface finishes with the use of lead-free solders and in lead-free assembly processes. Design/methodology/approach - The paper describes the various popular solderable surface finishes that are currently available. It then reviews them in terms of the required adaptations necessary to meet the requirements of the Restriction of Hazardous Substance (RoHS) Directive and to ensure compliance, whilst meeting the performance needs of the product. Findings - Some of the available and popular finishes, such as organic solderability preservatives and tin require modifications while, others including silver, direct immersion gold and electroless nickel immersion gold are transitioning well into the world of lead-free. Electroless nickel, electroless palladium, immersion gold is one finish that performs better with lead-free assembly than it did with conventional eutectic solder-based approaches. Originality/value - The paper provides a concise overview of the implications for specific surface finishes when making choices for use with lead-free and RoHS compliant PCB soldering and assembly.