Mr Zhang I do think that EN/IG is a excellent way for PCB surface finsh treat if we could do a good control for the gold thickness and Nickel qulity.As we known,the gold layer will be removed in the solding procedure. A thin gold layer will protect the nickel which have a good soldability. Or you can select immersion tin procedure. Chemical deposit surface finsh like immersion gold,tin or silver is provided with a well contributed plating layer. it will be good for BGA solding! I'm not a export for this field,I just want to show my idea! -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Shoukai Zhang Sent: Wednesday, July 11, 2001 05:27 PM To: [log in to unmask] Subject: [TN] PCB surface finishes Dear TechNetters: As we know that the preferred metal surface finishes are HASL, EN/IG (Electroless Nickel and Immersion Gold, and OSP etc. It's reported that EN/IG(also called immersion gold) suface may lead unreliable solder joint for BGA component, and suggest do not use immersion gold for designs that have BGAs. Please give your advices. Thanks with best regards, Zhangshoukai, PE, Huawei Technologies. ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------