Rudy, You are correct the boards do not have buried vias, but the
delamination does not necessarily locate adjacent to a hole.  Tests on bare
boards showed that they do occur primarily at one end of the PWB on layer 5
of 8.  The delaminations occur on the "sawtooth" side of the copper.
Additionally, examination through the laminate on the secondary side (layer
8) revealed black patchy areas over large land patterns or ground planes on
layer 7.  These also occur on the sawtooth side of the copper.  Although
these areas have not delaminated, I have confirmed that the laminate resin
does not bond to these areas and EDS showed the same presence of sulfur and
tin that was observed on the delaminated surfaces.  Do you know what
chemical preparation the sawtooth side of the copper is exposed to in order
to improve adhesion?

Thanks Rudy for your time.
Best Regards,
Jeff

-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, February 13, 2002 3:33 PM
To: [log in to unmask]
Subject: [TN] Delamination


In a message dated 2/13/02 2:58:07 PM Pacific Standard Time,
[log in to unmask]
writes:

<< I am looking for some information regarding the preparation of copper
foil
 for adhesion to internal laminate layers in the construction of PWBs.  I am
 presently experiencing delamination of the copper from the laminate prepreg
 on an internal layer after IR reflow exposure.  EDS of the delaminated
 surfaces showed localized, high-concentration of sulfur and tin on the
 copper surface >>

Jeff:  I assume that this delamination is occuring adjacent to drilled
holes?
 These are not buried via boards are they?

Rudy Sedlak
RD Chemical Company

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