Hi Roger,
don't tell me you work in Newcastle, was there last week, could have brought some job with me for you, OK, may be other occasion. What I wanted was having Via's opinion about bleeding from solder mask when selective Ni/ immersion Gold is applied. Also about Lead Carbonate and Adipin Acid and such stuff in vias bleeding up on solderpads during solder oven process. Been looking at samples from you before. May speak offline with you later, today other UK Co will solve the problem (I hope).
As for Humbria my wife and I lived in Otterburn Tower from AD1330, I love the moors up there, also like Balvini and Ad Cnoc.
Back to issue, good to hear plasma tricks or/and vacuum bake can make bad boards useful again. But according to specialists on my company you (Via) and others do other things when you get 'dirt' on pads, namely some kind of activation by means of Purasolve or special mild acidous mixtures. We tried such an activation bath in order to get better solderability on ENIG SMD PWBs, but found no improvement. Our solder test is this: screenprint solder spheres approx. 1/3 of pad dia and let pass oven at normal. Wetting diameter and yield is measure on what good surface we have to do with.
What do you thing in general, general Massey? Is 'reactivation' as described a recommended way? Mother's all-curing recipe, do you have that?
Ingemar Hernefjord
Ericsson Microwave Systems
-----Original Message-----
From: Massey, Roger [mailto:[log in to unmask]]
Sent: den 21 september 2000 09:39
To: [log in to unmask]
Subject: Re: [TN] Silver Epoxy Bleed on imersion Ni Au PCBs
Dave,
In a previous life as a supplier of a similar automotive sensor, we
found that the vacuum bake recommended by Steven when combined with using
the absolute minimum of epoxy did the trick, easy to say I know but it took
us weeks to get the thing sorted. Also found that plasma cleaning after
bond helped a bit with fighting off resin bleed, dont know why it just did
Good luck
Roger Massey
Via Systems - Tyneside
-----Original Message-----
From: Creswick [mailto:[log in to unmask]]
Sent: Thursday, September 21, 2000 3:29 AM
To: [log in to unmask]
Subject: [TN] Silver Epoxy Bleed on imersion Ni Au PCBs
Dave,
In the hybrid (or MCM) industry we have found a vacuum bake to be helpful in
this situation.
Try 50 mT @ 150°C for 2-4 hours.
Steven Creswick
CTS RFIM
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