Hello Technetters: I'm trying to develop and optimize a process for the following: SMT part where the bottom of the device (gold over nickel) will be soldered to a gold-plated copper surface (50-150 uin Ni, 3-8 uin Au) below the top of the board surface. The copper surface is actually a "coin". The pcb is milled from the bottom-side to a specific ground plane. The coin is then hi-temp soldered (Sn95Sb) to the ground plane layer (this is done at the board fab. shop). The manufacturer of the smt part recommends a pure indium foil .25" x .25", .003" thick. The component also has about thirteen gull-wing leads that depending on the tolerance stack-up, may be reflow soldered or hand soldered. We're going to run three replications of an L9 DoE (four factors, three levels) to develop and optimize the process. So, several questions: Where I'm soldering two gold surfaces, and low-temp is recommended, is indium the best choice? Any suggestions on how to evaluate the results of the DoE? X-Ray, cross-sections, pull-tests, cleanliness? Thanks for any input, Valquirio N. Carvalho --------------------------------------------------------------------------------- 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 e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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 ---------------------------------------------------------------------------------