Over the last few years, the topic of ionic contamination of electronic boards has become increasingly relevant, with the latest revision of the J-STD 001 standard, the technical commissions of the Association Connecting Electronics Industries (IPC) have suggested a new point of view to evaluate the quality of devices that arise from such objects.
Some of the anomalies on electronic boards can be traced back to contamination causes present
on them due to processing residues: The contamination value represents the set of polluting agents remaining from the production processes present on an electronic system. This residue can be ionic or non-ionic: the ionic one is made up of atoms or molecules/particles, which can dissolve in ionic form in a water/alcohol solution and become conductive
(dendritic formations) in certain environmental conditions and/or use of the boards, therefore creating defects in operation and reliability over time.
The non-ionic residue is given by elements without conductive properties in any form, which although remaining on the board after production and assembly do not generate functional problems.
In terms of the reliability of electronic devices, therefore, the focus has been on the content of the ionic residue of PCBAs and their integrated PCBs rather than other residues.
Ionic compounds that may be present during the production of PCBs and PCBAs include:
• Generic salts
• Organic and inorganic acids
• Flux activators
• Chemicals derived from metal plating processes (PCBs only)
• Human sweat
The set of these compounds generates the overall residual ionic content of a printed circuit board or an electronic board, but each of them, based on its own quantity, induces specific contraindications that are more or less serious and not general.
Nortech Elettronica, therefore, has undertaken to support Customers in the analysis and prevention of aspects related to ionic contamination, equipping itself with an Analysis tool in order to carry out tests and monitor the process and the product upon agreement with the Customer.
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