Wade, I have not worked specifically with NEC's TBGA. Most TBGA's use Sn63/Pb37 solder balls. Although it is common for some manufacturers to use silver Bearing solder balls. These are typically Sn62/Pb36/Ag2. The silver increases the yield strength and the electrical properties. It is also said to inctease the surface tension which helps in the self-alignment characteristics. The high lead solderballs are used on ceramic devices and some TBGAs with heat sinks or other heavy design features. In nearly all cases the high lead solder balls (Pb90/Sn10) as you described are attached with Sn63/Pb37 or Sn62/Pb36/Ag2. So you should be able to see a distinct "joint" between the high lead ball and the package. Hope this helps Regards, Russ Winslow Six Sigma 1940 Concourse Drive San Jose, CA 95131 [log in to unmask] http://www.sixsigmaservices.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Wade Oberle Sent: Thursday, February 11, 1999 8:29 AM To: [log in to unmask] Subject: [TN] Solder Composition for TBGA Dear Technetters, This may seem like a silly question to some of the veteran BGAers but here goes. I have a TBGA from NEC that I need to place. DO all TBGAs use alloy 10Sn and 90 Pb for the solder balls or could they use other alloys such as 63/37? I will leave a similar message on the NEC website and let you know the final answer. I viewed the online spec for this part number and there is no mention of the solder alloy. This makes me think it is an 'understood' industry standard that the alloy is 10/90. Regards, Wade Oberle [log in to unmask] ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################