How Clean is Clean Enough?

Highly dense assemblies with small gap distance between adjacent leads or interconnects increase the electric field and potential for leakage currents from contamination sources. Bottom terminated components soldered onto the PCB have flux residue trapped between the component body and board. Ionics in flux residue can exacerbate contamination levels under the component.

The theory behind this new test method is to provide a method for accurately measuring resistance of the contamination at the specific area under the component. The purpose of this research is to use this new test method to measure the resistance on non-cleaned and cleaned test boards using a low residue, rosin and water soluble solder pastes under a series of bottom termination components.