Hi, Steve
It looks like improper mask tenting, and severe de-wetting during the HASL stage, indicating the HASL process was reworked, which is what begins the dewetting process (copper is beginning to leach). Also, in picture #4, the copper specks all over under the mask indicate under-etching. I would not use these PWBs, as further de-wetting may occur during production. Nothing worse than starting the boards through reflow only to find out that you can't even touch up any solder defects without making them worse.
Nothing funny about it; I think it's time to qualify a new PWB supplier.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Friday, June 19, 2009 2:49 PM
To: [log in to unmask]
Subject: [TN] PCB problems
Dear Technos,
I have a few questions regarding a funny lot of PCBs we've received. Steve was kind enough to post the pictures, see
http://stevezeva.homestead.com/files/non_uniform_hasl.jpg <http://stevezeva.homestead.com/files/non_uniform_hasl.jpg>
http://stevezeva.homestead.com/files/non_uniform_hasl_1.jpg <http://stevezeva.homestead.com/files/non_uniform_hasl_1.jpg>
http://stevezeva.homestead.com/files/via_halo.jpg <http://stevezeva.homestead.com/files/via_halo.jpg>
http://stevezeva.homestead.com/files/via_halo_detail.jpg <http://stevezeva.homestead.com/files/via_halo_detail.jpg>
Out of the pack of 15 that I have inspected, most of them have some weird halos around all the vias, but no such issue around the component mounting holes. The pictures show the worst board, the rest have it to a lesser extent. What is it? Should this be a reject? Is this anything we should admonish our fab about?
Secondly, the SnPb HASL, is irregular on the pads, which is not out of the ordinary, but on some boards looks like in the pictures. I hesitate calling this de-wetting, since the wetting angles are good. Is it de-wetting? Should we reject the boards? I will paste the worst board I find and reflow it, to get an idea what happens during soldering, but I should also be able to help the incoming inspectors draw a line between good and bad in visual inspection of future lots...
Thank you,
Ioan Tempea, ing.
Ingénieur Principal Fabrication / Sr. Manufacturing Engineer
30 ans déjà! - Already 30 years!
950 rue Bergar, Laval, Québec, H7L 5A1
t : 450-967-7100 ext : 244
Mtl : 514-990-5762
f : 450-967-7444
[log in to unmask] <mailto:[log in to unmask]>
www.digico.cc <http://www.digico.cc/>
P N'imprimer que si nécessaire - Print only if you must
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 15.0
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
-----------------------------------------------------
|
