Nicholas,
It is Residual Organic Solvent Extraction testing. Otherwise known as SEC
Solvent Extraction Conductivity or IONIC EXTRACT CLEANLINESS testing.
I am sure you will be familiar with this test method but please bear in mind
that it will only identify ionic residues that may be harmful but not any
non-ionic residues which may also be harmful. Furthermore, it is of
questionable use if you are operating a no-clean process because many fluxes
should not be cleaned and this test method does exactly that.
The method used may also impart different "cleanliness" values and you need to
apply the equivalency factor for the system used. Also, high pressure spray
systems, such as our ICOM series, provide superior extraction to those relying
on immersion.
You may also consider that the "cleanliness" value, presently recommended at
less than 1.5 microgrammes of sodium chloride equivalence, also means that it
is acceptable to leave UP TO that amount on every square centimeter of your
assembly! If you manufacture fine pitch, BGA, COB and other "exotic" chip
scale packaging, then this value will almost certainly prove too high.
For the above reasons, Surface Insulation Resistance (SIR) testing is becoming
far more relevant and if you would like some further info on that - because
guess what; we do those too - then let me know.
Sorry to give you such an extended reply, but the Americans are on holiday -
for some reason, we British aren't too sure why! - and my e-mail cupboard was
not very full.
Graham Naisbitt
Concoat Ltd Email: [log in to unmask]
Alasan House, Albany Park Tel: +44 (0)1276 691100
Camberley, Surrey GU15 2PL UK Fax: +44 (0)1276 691227
-----Original Message-----
From: TechNet On Behalf Of Nicholas Kane
Sent: Monday, November 17, 1997 10:55 AM
To: [log in to unmask]
Subject: Re: [TN] Do we really need ionic contamination measurement
equipment?
Please, can you tell me what ROSE is?
Thankyou
At 09:53 15/11/97 UT, you wrote:
>Ken,
>
>Your wash system is tracking the resistivity or conductivity of your rinse
>water and your filter plant is taking care of such contaminants that are
>entering the process.
>
>The question is how much contamination is on the assembly, and has it all
been
>removed? I doubt that you can accurately maintain the amount of contamination
>that is being applied to your assembly both in your process and that of your
>PC Fab shop.
>
>It is therefore a good idea to conduct regular ROSE tests to ensure that your
>process is always under control. The sampling rate to achieve that is another
>subject that should be addressed.
>
>Graham
Naisbitt>---------------------------------------------------------------------
------
>
Nicholas Kane
Axion Australasia
Suite 3, 651 Canterbury Road
Surrey Hills
Victoria 3127 Australia
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