Hi Genny,
Why would you want to use Cu balls--they do not improve reliability, because the ball is too rigid and you wind up with 2 very thin solder joints. Now polymer balls covered in Cu and solder is another matter--they improve reliability.




Werner


-----Original Message-----
From: Genny Gibbard <[log in to unmask]>
To: [log in to unmask]
Sent: Wed, 17 Sep 2008 7:00 pm
Subject: [TN] Copper BGA balls








Anyone have experience with components using a tinned copper ball
instead of a SAC alloy solder ball?
Have you ever X-rayed one?
We are seeing voiding that does not meet the IPC-7095B spec for incoming
inspection with a transmission x-ray.  However, we don't know if this is
a concern for this type of ball, or if this spec even applies to this
type of ball.  I don't think these are meant to collapse and mix with
the solder on the board, like a normal solder alloy ball might. 

Once again, thanks in advance for sharing your knowledge.

Genny 

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------



 





---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------