Subject: | |
From: | |
Reply To: | Leslie O. Connally |
Date: | Wed, 13 Jan 1999 08:13:51 -0600 |
Content-Type: | text/plain |
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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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