ROSE testing a post-reflow assembly which has been reflowed using no-clean flux may not yield information that is helpful. No-clean flux technology works by encapsulating the flux's activators and other chemical constitutes that would be harmful if left un-encapsulated on the assembly. The ROSE tester will measure both encapsulated residues and un-encapsulated residues. It cannot discern the difference. The ROSE tester will provide a bulk (totalized) value. It is impossible to tell how much of the residue detected was harmful (un-encapsulated) or non-harmful (encapsulated).
If one desires to compare one no-clean brand from another by comparing the total residues after reflow, a ROSE tester would be beneficial. It is not possible to extrapolate that information into likelihood of ECM failures as it wouldn't know how much of the totalized residue volume would have been exposed verses encapsulated.
I hope this information is helpful.
Mike Konrad Aqueous Technologies
konrad@aqueoustech.com
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