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Reply To: | TechNet Mail Forum. |
Date: | Thu, 22 Jan 1998 07:49:05 +0200 |
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At 09:30 22/01/98 PST, you wrote:
> Hi all,
>
> Our ammonia etcher is followed by a replenisher rinse consists of 4
> cascade rinse chambers. As I understand, all ammonia etchers are
> followed by some cinfiguration of replenisher rinse, and when I ask
> what is the purpose of it, I was told that the rep. rinse is to
> 1) Decrease the copper content in the subsequent rinse water
> 2) Increase the copper content in the etchant that enter the etcher
> 3) Give a finishing touch to the etched panels
>
> I understand point#1, but not #2 and 3. Why would one want to increase
> the copper concentration in incoming etchant? Won't that defeat the
> purpose of feeding "fresh" etchant? And how does rinsing in cold,
> fresh etchant give a finishing touch to the etched panels?
>
> Regards,
>
> Yee T.G.
> Hadco Corp.
Your point 2 Is not clear to me either . Regarding point 3 : from my own
experience this is quality of rinsing . Alkaline etching solutions creates
sediments while diluted with water , there are also monovalent copper
chlorides , which are insoluble in water . All this is easy removed by fresh
etchant .
This is important point for someone , who is still running reflow of
tin-lead . As well these residues are contributing to copper content in
solder stripper .
Regards
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