Scott, First, one must know what bonding technology the Customer is using. Is it ultrasonic aluminum of thermosonic gold? If it is aluminum, then the gold is effectively only there to protect the nickel - to provide a good, clean, nickel surface to bond to (with the 3-5 uinches of gold efectively excluded from the bond). The exception being if someone has put hard gold on the surface, then it may have been better to leave the gold off altogether. If the application is thermosonic gold (where the ultimate goal is a gold to gold bond), then PURE, SOFT gold of a MINIMUMm of 10-15 uinches is normally required. If the board is scheduled to see multiple bakes, or elevated temp storage prior to wirebonding, increases in gold plating thickness are very helpful. I believe the KEY critical parameter here is PURE gold - such elements as thallium, cobalt, copper, etc co-deposited in the gold plating as grain refiners, etc. can extremely quickly ruin a bondable surface. A 'pore free' plated film, if there actually is such a creature, also facilitates the long term preservation of the plated surface, and its subsequent bondability. There have been many other posts concerning adhesive resin bleen, solder mask bleed-out etc. Naturally, these also may have an effect. Possibly, some of the more 'plating inclined' individuals out there can add a few comments. From a User's perspective, if you can find and nurture a good plater, your life becomes tremendously more forgiving. Steve Creswick - CTS RF Integrated Modules ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################