David

This is another really misleading statement:
>
> BTW Omega meters are NOT to be used to determine if you have ionic
> contamination.
> Only to used used to detect variations in conductivity from one
> "batch/production run" to another.
>
These instruments were intended to detect ionic contaminants on the surfaces
under test. You measure the resistivity or conductivity of the test solution
(IPA/Water) before testing and again after testing - any change to the
resistivity or conductivity is what in your opinion?

What is true, is that these machines were only ever intended to be used as a
process control method. Ask Dr Jack Brouse.
--
Regards Graham Naisbitt

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> Polyimide is well known as a moisture absorbent. I suspect this will be
> a factor in your problem.
>
> David A. Douthit
> Manager
> LoCan LLC
>
>
>
> Russell Burdick wrote:
>
>> Here's a question for all you electrical fans...( ha, ha, ha, not
>> those type
>> of shorts)
>>
>> We are getting high resistance shorting on multilayer polyimide only
>> boards.
>> Inner layers test out with no problem. Immediately after outer layer etch
>> there are the shorts. Omega meter testing shows no ionic contamination at
>> this stage. Baking prior to ET reduces the number of shorts, although
>> after
>> a few days the shorts are back. Construction of board is foil copper at
>> lamination, not cap-core.
>>
>> As usual, any and all help is greatly appreciated.
>>
>> Russ
>>
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