In a message dated 8/3/2005 11:21:06 PM Pacific Daylight Time, 
[log in to unmask] writes:
Would US affect the peel strength of very fine tracks (<100 µm)? 

Good question, Brian. 

Lower profile copper treatments are generally required for finer features. 

It would seem then, by extension, that terminations on a BGA package 
substrate be similarly vulnerable. 

(I read and understand that it was manifest only on PCB substrates and only 
of BGA land patterns. Is this correct?) 

Some more questions (perhaps already asked by investigators) Was there a 
pattern or tendancy to the failures in terms of physical location? was it random? 
Was it BGAs of all I/O counts or specific ones? Plastic or Cermaic? Where 
there differences between different pitches?

An interesting engineering forensics problem...  

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------