Dave, Since we need to keep this forum technical, I won't get into what happens when we "AssUme" a process is in control.... What are you masking with? If you are masking with Kapton or something similar you are likely imparting pressure on the top of the BGA. When the BGA heats up and the sphere become liquid, the downward pressure will cause bridging. WHY are you masking? Have you considered trying the wave process without masking? It may also be possible that solder is coming up through the vias. How thick is the board and how large are the vias? Are the vias connected topside to the solder pads? -Carrie -----Original Message----- From: Dave Chapman [mailto:[log in to unmask]] Sent: Monday, April 28, 2003 10:03 AM To: [log in to unmask] Subject: Re: [TN] BGA Happy Monday, I have a BGA 256 Tundra which has no shorts in SMT (we x-rayed all 16 boards) When it goes over the wave we get a short or two. Please assume the wave is in control. We mask the topside of the BGA because there are a lot of vias which when they test it would leak and not get pulled down good in the fixture. I need the vias on the bottomside under the BGA to be filled with solder for testing so I can't mask the bottom. What should I do? Dave Chapman Manufacturing Engineer Circuit Service Inc. --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- -------------------------------------------------------------------------- DISCLAIMER: The information contained in this communication is confidential and may be legally privileged. It is intended solely for the use of the individual or entity to whom it is addressed and others authorized to receive it. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or taking any action in reliance of the contents of this information is strictly prohibited and may be unlawful. Stork is neither liable for the proper and complete transmission of the information contained in this communication nor for any delay in its receipt --------------------------------------------------- Technet Mail List provided as a free 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/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 1.8e 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------