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Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 10 Sep 1999 10:06:52 +0800 |
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Dear Jim,
I am interested to know where and how we can acquire the information for
ammonium sulphate etching system is etching faster than that of ammonium
chloride.
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At 02:45 PM 1999/9/9 +0100, you wrote:
>For the best undercut Cupric will etch slower than cuprammonium chloride.
>It is possible to make cupric etch faster than cuprammonium chloride by
increasing the acid normality,at the expense of undercut.
>Cupric etch speed can also be increased by additions of sodium chloride
but then your metal recovery guys don't want to know.
>Note that cuprammonium sulphate is even faster than cuprammonium chloride.
>
>Jim Douglas
>Kam Circuits
>
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Albert Mok
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