Ionic Contamination Testing

If no-clean flux is reflowed correctly, many of the activators are encapsulated within the resin residue left behind after reflow. An ionic contamination test cannot differentiate between ionic residue that was encapsulated (not harmful) and residues that were not encapsulated (harmful). Keep in mind however, when no-clean flux is used and in cases when no-clean flux is actually not cleaned (today more than 50% of no-clean is cleaned), nothing is removed from the assembly. When assemblies are cleaned, it's not just flux that's removed. All process residues are removed (board and component fabrication residues as well as human and assembly residues). The totality of residues (process and flux) are increasingly harmful to an assembly. Even though ionic contamination testing may not discern between harmful and non-harmful residues, it still may provide value.

I hope this helps.

Mike Konrad

Aqueous Technologies

www.aqueoustech.com

konrad@aqueoustech.com

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