i've been listening to copper plating discussion for the last two weeks - n
heard some very interesting info from the forum - but - there already is a
commercial process that works on reverse pulse method - that has been in
operation in Canada for almost the past three years.


reverse pulse - distributing the regular cathodic DC current by short anodic
pulses. The current density applied during the reverse phase is at least
double that of the forward phase during actual plating. period of reverse
pulse usually lasts between o.5 to 1 ms - frequency of the produced AC current
is varied between 50 and 100 Hz.

the solution itself is almost standard make up - aigtation - enductors -
vibrators - no air ( this no air has been in existence with DC for over 15
years )

hole to surface is almost 1:1 - depending on actual board design -
can do blind via's to 4 mil diameter - 5mil deep
reduced plating time between 30 - 50% ( depending on board thickness &
circuitry configuration )

copper elongation - between 18 - 22.2 %
current density ( cathodic ) - 30 - 40 ASF
tensile strength - 33.7 - 34.2 / kNcm2
SEM - crystal grain structure between 2 - 5 microns ( no laminated layers )
thermal shock - 5 minimum

this entire process - equipment and chemistry has been running in Canada for
close to 3 years.

I am enclosing a x-section of one of these boards - should you need more
information - let me know