Phil/Rudy: Just a quick addition on the Sulfuric/Hydrogen Peroxide etch
chemistry. You have to be careful on the loading factor ie sq ft/gal due to
the exothermic nature of the chemical reaction during etching. Most of these
baths require some type of cooling or two tanks to alternate between.
Also on the Sodium Persulfate concentration,it can be run down in the 30
grams/liter range and still produce acceptable etch rates for an electroless
line. Of course you know how those chemical salesmen are, big on dragout
chemistry :>)
Regards
Michael Barmuta
Staff Engineer
Fluke Corp.
Everett WA
425-446-6076
-----Original Message-----
From: <Rudy Sedlak> [mailto:[log in to unmask]]
Sent: Tuesday, June 12, 2001 1:42 PM
To: [log in to unmask]
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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