This post hopes to shed some light on the pros and cons of the four most dominant PCB surface finish solutions on the market: Organic Solderability Preservative (OSP), Electrolysis Nickel Immersion Gold (ENIG), Electroplated Nickel Gold and Immersion Tin or Silver. The following post applies to Rigid Printed Circuits Boards (PCB) and Flexible Printed Circuit (FPC).
Note: PCBs are generally made of rigid materials and will not bend during their application. FPCs are usually thin and made of materials capable of bending and/or movement during application. Processing and application requirements dictate whether the PCB surface finish is electroplated, electrolysis, immersion or deposited.