Ben, Electroless Nickel/Immersion gold (ENIG) is a surface finish in its own right. It does not involve electroplating after. In most shops it is applied after soldermask cure, others apply the finish then follow with the soldermask application and cure. Electroless nickel (120 - 200 uins) is the diffusion barrier and the soldering surface. The immersion gold surface (2 - 4 uins) is there to protect the Ni from passivation and/or oxidation until assembly time. Immersion Gold is POROUS. At assembly the gold is dissipated into the solder, and a Nickel /Tin solder joint is formed. A defective/corroded Ni surface "Black pad" will not form a good solder joint. The Black pad issue is presently well understood by your supplier and can be avoided. A contaminated gold surface (soldermask, organic residues etc.) will also not give a good solder joint. George Milad Technical Mkt. Mngr Shipley Co. (516) 868-8800 ext. 269 --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------