Hi Rudy,
Three points:
1. Electroless copper etches faster than base copper or electrolytic copper.
2. Watch for excessive overetching inner layers (eg multiple passes etc)
3. Third formulation based on potassiumperoxomonosulphate also loved by
supply houses.
Best Regards,
Ken McGowan.
----- Original Message -----
From: "<Rudy Sedlak>" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, June 12, 2001 7:42 PM
Subject: Re: [TN] Sulfuric peroxide preplate microetch
> In a message dated 6/12/01 8:57:10 AM Pacific Daylight Time,
[log in to unmask]
> writes:
>
> Phil: Happy to help, do be careful, you have made a coupla errors that
could
> have been dangerous if implimented....
>
> << What it the standard formulations for sodiium peroxide or ammoniun
peroxide
> microetch
>
> You mean, Phil, Sodium or Ammonium PerSULFATE, (There exists Sodium
Peroxide,
> and you do not want to go near the stuff.....)
>
> Figure 8 oz/gal (60 grams/liter) Sodium Persulfate, which is preferred
over
> the Ammonium salt, because the Sodium Salt does not chelate, thus waste
> treats easily. Add 1-2% Sulfuric Acid, you there.
>
> and the sulfuric/hydrogen peroxide
>
> The big problem with sulfuric/peroxide is that the peroxide is inherently
> very unstable, and you gotta buy a proprietary additive to keep it stable,
> otherwise, things can get a little unstable as you introduce Copper into
the
> solution.
>
> Also is the temperature elevated or at ambient temperture.
>
> Temp usually runs ambient to slightly elevated (under 100 F) depending on
> spray or soak, immersion time, etc.
> >>
> Rudy Sedlak
> RD Chemical Company
>
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