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60 DESIGN007 MAGAZINE I SEPTEMBER 2022 Article by Anaya Vardya AMERICAN STANDARD CIRCUITS Introduction One of the biggest challenges facing PCB designers is not understanding the cost drivers in the PCB manufacturing process. is article is the latest in a series that will discuss these cost drivers (from the PCB manufacturer's perspective) and the design decisions that will impact product reliability. Final Finishes Final finishes provide a surface for the com- ponent assembler to either solder, wire bond, or conductively attach a component pad or lead to a pad, hole, or area of a PCB. e other use for a final finish is to provide a known con- tact resistance and life cycle for connectors, keys, or switches. e primary purpose of a final finish is to create electrical and thermal continuity with a surface of the PCB. ere are a number of final finishes in use in the industry today, including: • ENIG (electroless nickel, immersion gold) • ENIPIG (electroless nickel, immersion palladium, immersion gold) • ENEPIG (electroless nickel, electroless palladium, immersion gold) • IAg (immersion silver) • ISn (immersion tin) • Sulfamate nickel/hard or soft gold (Electrolytic nickel/gold) • HASL (hot air solder leveling) › SnPb (63/37 tin/lead) › LF (lead free) • OSP (organic solderability preservative) Final finishes are primarily application driven, so there are a number of considerations DFM 101: Final Finishes—ENEPIG and IAg