Pete,
I agree with Randy. Etch the sample to see where the etchback ends along the foil. IPC-6012C-2010 paragraph 3.6.2.6 and Figure 3-11 explain how to measure the maximum allowable copper beyond the end of the foil.
Bill
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Reed, Randy
Sent: Tuesday, August 13, 2013 6:02 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Wicking Requirement IPC 6012B/3A vs 6013C/3A
Hi Pete -
I cannot see the demarcation line on the foil. This needs to be visible to determine how to start the wicking measurement. The wicking measurement is an after etch inspection. The measurement at the end of the wicking (closest to the m in mils) is set correct.
The desmear method(s) is not relevant to the wicking measurement. Whatever combination of processes that are being used to clean the holes, the wicking maximum limits cannot be exceeded.
The sample needs to be etched to provide insight on why the wicking exceeds the maximum limit. The demarcation lines will provide clues on the drill, desmear, and plating integrity/quality.
One observation is the core material had the wicking failure and the neighboring prepreg dielectric opening does not appear to the same wicking length. Does this observation track true for all the dielectric openings? If this is the case, this may be a material issue from the laminator and/or a press cycle issue. More information would be needed to explore this as a cause for the failure.
Randy
Randy Reed, ASQ CQE
Reliability Lab - N.A.
Viasystems Group, Inc.
Forest Grove, Oregon
Phone: 503.992.4421 Cell: 503.545.0150
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Pete Menuez
Sent: Tuesday, August 13, 2013 2:19 PM
To: [log in to unmask]
Subject: [IPC-600-6012] Wicking Requirement IPC 6012B/3A vs 6013C/3A
Hello All -
This isn't the best picture but it is all I have.
This cross section is being evaluated to IPC 6012 Rev B Class 3A and is being rejected for wicking in excess 2 mils. Is this, in you all's opinion, wicking or is this the effect of plasma etch/resin removal/glass etch and not wicking? How should this be evaluated under B/3A?
How would this be evaluated in 6012 Rev C Class 3A? Could you even evaluate it since this is before etch?
Comments are greatly appreciated. Btw, I'm not trying to save anything.
This panel has already been scrapped out - I have a presentation with my customer and I'd like to offer more opinion than just my own and the board fab.
Thanks,
Pete
Peter Menuez
Supplier Quality Engineering Manager
L-3 Communications Cincinnati Electronics
7500 Innovation Way
Mason, Ohio 45040
[log in to unmask] <mailto:[log in to unmask]>
513-573-6401 Voice
513-767-3778 Cell
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