The Gold Standard in PCB Finishes
ENIG consists of a nickel underlayer (3-7um, hard and flat) and a gold top layer (0.05-0.12um, oxidation protection). Gold does not tarnish - ENIG boards have shelf life measured in years. Best for fine-pitch BGAs (flat surface ensures every ball contacts its pad), wire bonding (gold-to-gold bond), and press-fit connectors (hard nickel layer withstands insertion). Thickness verified by XRF on every production panel to IPC-4552 specifications.
Other finishes available: Lead-Free HASL (standard, lowest cost), Immersion Silver (smooth surface for high-frequency), Immersion Tin (flat lead-free press-fit), OSP (lowest cost, short shelf life).
