Hello Technetters, I'm a new member to this board, and hope some technetters could void their opinions and advices on this issues. We are currently dealing with a 0201 SMT process and have some issues with a HASL 0201 landpatterns. The HASL PCB has non-uniformed finshed surface, and results in tombstones and solderballs after the reflow process. We then switch to Immersion gold 0201 landpatterns and the issues of solderballs and tombstones went away. The average cost different between HASl and Immersion gold (7-10 micron)is about 6 - 8 % in cost. Another PCB vendor introduced us to Immersion Tin (white tin) to reduce the additional cost of Immersion Gold pads (about 2-5 % cost different between HASl and Tin). We have used Immersion Gold in many of our prototype products and having really high yeilds, but we have not try the Immersion Tin pad finished and wonder if they behave like the Immersion Gold. The vendor also mentioned that the Tin finished will oxidize and have a shelf life of 12 months. BTW, We are using "No Clean" process with Convection air oven. Any technetter has experienced in both pads surface finished ( Gold Vs Tin) is greatly appreciates. Tuan Bui Process Dev Eng Conexant Systems Inc. --------------------------------------------------------------------------------- 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 the archives of previous posts at: http://listserv.ipc.org/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 ---------------------------------------------------------------------------------