Thomas:
A lot of personal preference. Part of my job is and always has been environmental protection and compliance. Nitrates are usually a lot easier to deal with than halides, and in this use you're looking for the action of the hydronium ion more than the anion. If the facility is set up for and uses HCl pretty much exclusively (and I know that etching operations frequently are), HCl will most certainly work.
... Bruce D. Bullough ...
Sebesta Blomberg & Associates
2381 Rosegate
Roseville, MN 55113
651-634-7344 (office)
651-634-7400 (FAX)
www.sebesta.com
-----Original Message-----
From: Thomas Laupa [mailto:tlaupa@frii.com]
Sent: Tuesday, May 21, 2002 9:14 AM
To: <a href="/group/PipingDesign/post?postID=4u6Hl3Qd8fsRNuX_QgzPb02U8ZK32YgZjuM-PVVruOZJAf-nl7nbIlUwxRAj26adYm1j5U3b14GXKmH3nueN40FEmcXe1Q">PipingDesign@yahoogroups.com</a>
Subject: RE: [PipingDesign] Piping Systems for High Purity Deionized
Water
Bruce:
thank you very much for the recommendation. very cogent and complete.
i'll consult with the process guys for their input.
one question, why nitric acid rather than hydrochloric?
At 09:01 AM 5/21/2002 -0500, you wrote:
>Thomas:
>
>I can give a generalized recommendation, but specifics need to be
>tailored to the specific use. There area also considerations regarding
>capabilities for rinsing, much the same as one would do for pickling or
>passivating in place. Start with an organic solvent rinse (10% methyl
>or ethyl alcohol is fine, but generally avoid oxygenated organics),
>preferably circulating for several "volume changes", then a "tap" water
>rinse, then assuming that the circuit boards are acid etched, follow up
>with dilute nitric acid solution (not more than 1 Molar, not less than
>0.1Molar is needed), then a thorough rinse with the pure water until
the
>pH gets up to about 6.5. Some of the wash solution selection depends
on
>pipe assembly techniques (fitting), too.
>
> ... Bruce D. Bullough ...
> Sebesta Blomberg & Associates
> 2381 Rosegate
> Roseville, MN 55113
> 651-634-7344 (office)
> 651-634-7400 (FAX)
> www.sebesta.com
>
>
>-----Original Message-----
>From: Thomas Laupa [mailto:tlaupa@frii.com]
>Sent: Monday, May 20, 2002 10:59 AM
>To: <a href="/group/PipingDesign/post?postID=4u6Hl3Qd8fsRNuX_QgzPb02U8ZK32YgZjuM-PVVruOZJAf-nl7nbIlUwxRAj26adYm1j5U3b14GXKmH3nueN40FEmcXe1Q">PipingDesign@yahoogroups.com</a>
>Subject: RE: [PipingDesign] Piping Systems for High Purity Deionized
>Water
>
>
>Bruce:
>
>per your recommendation, and some library work, looks like we'll use
>PVDF. what types of cleaning procedures would you suggest?
>
>
>At 08:00 AM 5/20/2002 -0500, you wrote:
> >"High Purity Water" is a relative term. At a certain point, PVC can
> >only serve after it's been leached (and therefore weakened). Go w/
> >resistoflex, PVDF or glass lined, but any need to be properly cleaned
> >and installed. Not all glass is even right (and everyone hates to
fit
> >or pay for glass). Always be aware that ultra pure water is very
> >corrosive!
> >
> > ... Bruce D. Bullough ...
> > Sebesta Blomberg &
Associates
> > 2381 Rosegate
> > Roseville, MN 55113
> > 651-634-7344 (office)
> > 651-634-7400 (FAX)
> > www.sebesta.com
> >
> >
> >-----Original Message-----
> >From: Thomas Laupa [mailto:tlaupa@frii.com]
> >Sent: Friday, May 17, 2002 3:03 PM
> >To: <a href="/group/PipingDesign/post?postID=4u6Hl3Qd8fsRNuX_QgzPb02U8ZK32YgZjuM-PVVruOZJAf-nl7nbIlUwxRAj26adYm1j5U3b14GXKmH3nueN40FEmcXe1Q">PipingDesign@yahoogroups.com</a>
> >Subject: [PipingDesign] Piping Systems for High Purity Deionized
Water
> >
> >
> >Gents:
> >
> >Have been given a project involving high purity water used for
washing
> >integrated circuits. Looking for some advice:
> >
> >1>What piping systems are generally used? Existing system is a
> >hodgepodge
> >of PVDF and PVC.
> >2>Can anyone recommend standards or specifications?
> >3>Can anyone recommend good reference material?
> >
> >Thank you in advance for your help.
> >
> >
> >
> >_____________________________________________________
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Received on Tue May 21 10:38:00 2002
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