Hi Francis,

I't been some time since I worked with electroless, but I do remember a bit.
One thing I do recall is that the bath activity is very closely tied to the
formaldehyde concentration. You may want to monitor that a little closer. I
recall that if we did not easily detect the formaldehyde odor, we gave the bath
a slight kick ( following a real analysis) of formaldehyde and that usually got
the bath going again. I don't know what you are monitoring in the bath, but a
good indication the bath activity is an E-mix electrode pair, which is simply a
pH reference electrode and a platinum electrode on which copper is plating. The
Mixed potential (or potential difference between them)  should be in the range
of approimately 650 millivolts.

Good luck,
Les

>  From: Francis Lai <[log in to unmask]>, on 1/12/99 8:55 PM:
>  Every morning, after adjusting of chemicals, we run a 1"x1" pure teflon
>
>  which is sodium etched dummy from the PTH line. The last step of the PTH
>
>  line is 30 min of electroless copper plating. Every morning, the dummy
>
>  reads a copper thickness of 60-70 u in. However after running about 3-4
>
>  hours of real production panels in the same PTH line, the copper thickness
>
>  measured dropped to 25-30 u in. We make addition of chemicals every 2 hours.
>
>  I am just curious to know why. There are no PTH voids. Just copper thickness
>
>  is low.
>
>  Can any one help.
>
>  My e-mail : [log in to unmask]
>
>  Thanks!!!!!!!
>
>  Francis
>
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