We are using High Lead Balls on a custom BGA device.  The balls are 25 mil dia.
and the pad is 22 mil.  The BGA uses a FR-4 substrate.
I am trying to establish an inspection criteria for the solder fillet between
the PCB and the ball as well as the BGA FR-4 substrate and the ball.
Do I want the solder to come up to 50% of the ball height, both from the
substrate and PCB, creating close to a column, is 25% of the ball height
good enough, or maybe something in-between?   What is the typical criteria?

Best Regards,

Mike Forrester
LeCroy Manufacturing Engineer

##############################################################
TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################