20 The PCB Magazine • May 2015
Michael Carano is with
RBP Chemical Technology.
To contact the author,
click here.
and phosphorous dispersion (shown as the dark
areas). As one views each of the structures, the
differences are remarkable.
The anodes from Manufacturer 1 show large
and uneven grain boundaries. In addition, the
phosphorous is unevenly distributed. This leads
to high organic additive consumption, anode
sludge and plating roughness. The anodes from
Manufacturer 2 and 3 are the ideal quality re-
quired for PCB plating for high-aspect ratio
holes.
Summary
While electroplating PCBs with aspect ra-
tios greater that 12:1 is probably best accom-
plished with periodic pulse reverse plating, di-
rect current plating will produce high-quality
circuit
boards with aspect ratios up to 12:1.
This requires that several parameters be opti-
mized for throwing power and plating distri-
bution. These parameters include plating cell
design, high quality copper anodes, solution
agitation with use of eductors, anode length
and placement and proper selection of organic
plating additives and the electrolyte (inorganic
chemistry).
PCB
references
1. D.R.Gabe, Trans IMF 2003, 81, 7. Ward.
2. Yung, E.K. and Romankiw, L., "Fundamen-
tal Study of Acid Copper Through-hole Electro-
plating Process," Symposium on Electrodeposi-
tion Technology, The Electrochemical Society,
Pennington, New Jersey, pages 612–635.
3. Chuck Walker and Steve Doyle, Electro-
plating: The Importance of Copper Anodes,
Finishing World.
realtimewith.com
CliCk
To View
VidEo intErViEw
iPC Plating Committee Chair
George Milad explains the
procedure for generating
standards, with particular
reference to recent revisions
of iPC-4552 for eniG and
iPC-4556 for enePiC and dis-
cusses current developments
in
ePiG and electroless silver.
ENIG & ENEPIG IPC Standards Update
by Real Time with...
IPC APEX EXPO 2015
OPTIMIzATION OF ACID COPPEr ELECTrODEPOSITION PrOCESSES continues
FEaturE
