Seth, You said it yourself in the beginning as MCM's have used this technology for years. The plating overhang issue can be resolved using extra thick or additional plies of DF photo resist but you'll have a high mound left. Have pictures of this as well. I/we did this stuff many years ago as I indicated for through hole boards. Also did it in the early/mid 90's with early BGA types hoping to eliminate some processing problems not yet addressable. I worked with IBM, while working with Cray, a couple of years ago. They used the technology for then to be 3400 I/O MCM's. Who else is out there doing this with MCM's and "normal" PCB's? Still, the minimum thickness and ductility requirements must be in place no matter the overhang issue and its solution. MoonMan --------------------------------------------------------------------------------- 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 To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------