Ken

Following Brian and Lee's earlier postings, you have asked "What is the
acceptable Ionic contamination limit for Omegameter 600 and Ionograph 500
both made by Alphametals?"

Are you asking the right question? The existing specifications such as
IPC-JSTD-001 call for a level of less than 1.5 microgrammes/centimeter
squared of NaCl equivalence.

However, this also means that it is acceptable to leave UP TO 1.5
microgrammes of "salt" on every square centimeter of your assembly. If you
are involved with fine line, fine pitch and small chip scale packages, then
this level may well be far too high.

For this reason, many impose an empirical value of less than 0.2
microgrammes.

The acceptable limit for either machine will be sufficient salt to kill the
de-ionising filter bed - maybe also the resistivity / conductivity meter.

Trying to figure how clean is clean is a tough one. My view is that it would
be better / easier, to figure if your assembly is going to be reliable. You
can use to modern SIR techniques to achieve this. The if you find you have a
problem and want to analyse what it is causing the problem, then use Ion
Chromatography.

Hope this helps

Regards
Graham Naisbitt
[log in to unmask]
Web: www.concoat.co.uk
Concoat Ltd
Alasan House, Albany Park
CAMBERLEY GU16 7PH
Tel: +44 (0) 1276 691100
Fax: +44 (0) 1276 691227

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Ken Patel
Sent: Thursday, December 14, 2000 01:44
To: [log in to unmask]
Subject: [TN] Ionic contamination Limit


Guys,
What is the acceptable Ionic contamination limit for Omegameter 600 and
Inograph 500 both made by Alphametals?

re,
ken patel

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