Hi John,
You gave us a long story but little of the important information.
Let me see if I have this straight:
You have problems with a 10-mil-hole.
You see dog-boning [thin plating in the center] of the Cu plating in that
hole.
You sectioned a 40-mil-hole and the plating is uniform.
You do not say how thick the PCB is.
You do noty say how thick the Cu deposit is.
You do not say what, if any, of the Cu properties the shop has measured.
From what you have said, it is clear that whatever plating process this shop
is using,this process has run out of steam for the aspect ration represented
by you 10-mil-holes. most likely both in terms plating uniformity and most
likely Cu ductility.
Also, removing non-functional lands, particularly at layers 1, 2, 3 and n-2,
n-1 and n and particularly for LF-soldering, is bad practice.
Your coupons should contain the same lay-up as your PCBs, and should contain
both the smallest and largest drilled and plated holes.
I do not think that "ENIG microetching" caused your problems.
You also might want to take a look at the specifications your company wrote
for these PCBs.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
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