Our experience with soldermask tented vias indicated that it was not a robust process. On occasion there is a pin-hole in the mask and liquid is trapped in the hole and ejected during thermal excursions. -Al Onderick National Instruments -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] On Behalf Of [log in to unmask] Sent: Tuesday, March 22, 2005 7:35 AM To: [log in to unmask] Subject: Re: [TN] VIA Tenting Question The IPC has a task group writing a document regarding Via Protection and I personally think this is one of the most important topics needed to be covered by the group. The task group is D33-d and you can download the latest version of the document, which is scheduled to be released this summer from the IPC website. Recently we have performed numerous failure analysis on vias that have partial plugging/tenting that have contaminates trapped within the via from both the board fabrication and the assembly processes. The hole walls are bare copper and they did not survive the corrosion. There are so many things to consider when choosing what to do for via protection, but in my humble opinion if the barrels are left bare copper only complete plugs and tents have a chance of protecting the vias. If you are using ENIG in the vias then you can concentrate on what is needed for your assembly processes knowing the barrrels of the vias are protected from contaminates. Susan Mansilla Robisan Lab --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------