Both bare printed circuits (PCB) and assembled boards may contain post-processing residues that are “invisible” or not always visible, which can become dangerous in certain situations.
Indeed, during both PCB manufacturing and assembly processes, traces of substances (salts) may remain. If present in certain quantities, they can create poor insulation problems and/or, in certain humid conditions, lead to the formation of dendrites (whitish residues).
This “poor cleaning” of boards/PCBs results in malfunctions.
There are various analyses and regulations (unknown to most companies) that allow us to perform these tests, protecting us from “unwanted” future surprises.
Very often, these issues don’t appear immediately, but rather after a certain period on systems/equipment that are usually already in the field. (At the End Customer)
Situations may occur where the same product works correctly in some conditions while in other contexts and environments (perhaps more humid ones) it doesn’t work at all.
IPC standards (IPC-001 and IPC TM-650) exist to help us, both for “ionic contamination analysis of the PCB alone, and for” analysis of the assembled board. These standards address the matter precisely and accurately.
It should be noted that a good PCB supply specification also helps to address this matter
Tests can be performed using an instrument called Ionograph (a testing system), for example see http://www.aqueoustech.com/ where the board is immersed in a solution composed of deionized water and isopropyl alcohol (IPA).
This test, using the Ionograph, allows us to extract and measure the quantity of Halides present; specifically Bromine, Chlorine, and Fluorine (in the form of equivalent NaCl present in μg/cm2).
This method, invented in America in the early eighties, is known as ROSE; Resistivity of Solvent Extract.
In various applications (both PCBs and electronic assemblies), it is advisable to perform ionic contamination analysis; it’s a fast and precise system.
Prime, as a SOLUTIONS provider in the field of printed circuits and electronic board assembly, can help you guide a proper analysis of all aspects related to Ionic contamination, with precise, certain, and timely responses.
We hope this brief technical information has been helpful!
