Steve, Your complaint, if I read it correctly, is a classic one for all of those people that follow industry and military specifications regarding reliability, such as MIL-STD-217, and accelerated testing, such as JEDEC. The reality is that reliability does not work with a one-size-fits-all approach, but instead is sensitive to materials, geometry, and lifetime environmental loads. Many groups take a physics-of-failure approach to reliability, which allow them to accurately predict time-to-failure using a knowledge of wearout failure mechanisms, validated failure models, and acceleration factors that correleate results of accelerated tests to expected field behavior. Best Regards Craig -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Steve Joy Sent: Tuesday, June 05, 2001 12:10 PM To: [log in to unmask] Subject: [TN] voids in BGA, but really reliability in general I am a little confused about BGA voids and reliability. How many field returns per year do we collectively see? My experience over the last several years was 0. Don't recall ever seeing one. But we all build to specs that mathematically predict some defects. So where are they? So it must meaqn the spec requirements are excessively tight. The characteristic life curves I developed showed that assemblies are incredibly robust. Of course, that is using the accepted acceleration factors. Which is my point. Why can't we use realistic (or better-experimentally defined) limits? I have run assemblies beyond 1K cycles (of -45C to 85C) with 70% voids and seen no failures. I am talking millions of joints in many package styles. Is there any industry group looking at this kind of problem? Steve ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------------