Depends on weight, Hann. The heavier the package, the more compressed balls. If you talk collapsed balls. I have had a look on BGAs from some 200 up to 1200 balls, and with varying weight. They seem to collapse so that you get a delta from anything between 10% height reduction to 50%. The later are called 'squashy' by guru W. Notice that the delta can be both plus or minus! All balls are not necessarily compressed. If we have to do with a 'manta' package, the bowing can cause both elongated and compressed shapes. IBM Fishkill once put into my head that the resulting balls must have a barrel form, but I now learn that the shape is not so essential in most practical applications. But of cause the computer is right in theory. Ingemar -----Original Message----- From: Hann Pang [mailto:[log in to unmask]] Sent: den 29 mars 2001 18:53 To: [log in to unmask] Subject: [TN] Collasped Height of BGAs/CSPs HI Technet experts, 1) Can someone tell me what kind of heights i can expect between a 12mm x 12mm full area array BGA package and the substrate after reflow.? 2) How do they typically differ for Packages of different sizes, arrays, I/O counts and solder balls? Thanks in advance! Hann 3M --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------