Mornin' Kevin!

Are the vias supposed to be tented? If so, are they tented on one side
or both? You should expect the same sort adhesion over vias...could be
there's contamination that wasn't cleaned well prior to masking.

-Steve Gregory- 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Tuesday, May 16, 2006 7:31 AM
To: [log in to unmask]
Subject: [TN] Soldermask adhesion over vias?

Can I / should I expect the same level of soldermask adhesion over vias
as over the copper plane or laminate?  I have PCBs that have poor
adhesion of soldermask over the via pads, but acceptable everywhere
else.  Many vias are now bare copper, and the vias that are covered
easily fail any tape adhesion test.

How should I specify adhesion requirements on a drawing?  IPC-SM-840?

Thanks,



Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.




---------------------------------------------------
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
-----------------------------------------------------