Process Control of ENIG and ENEPIG Surface Finishes with X-Ray Fluorescence

Two very common uses of x-ray fluorescence (XRF) spectrometers are measuring specific coatings used in the manufacturing of printed circuit boards; ENIG and ENEPIG coatings. The ENIG coating is immersion gold plated over electroless nickel on the bare board (Au/ENi/Cu) while the ENEPIG coating has a layer of electroless palladium in between the gold and nickel (Au/Pd/ENi/Cu) because it acts as a diffusion layer and limits nickel diffusion to the gold layer. These coatings have been available for some time and have become popular within the electronics industry because they provide a lead free option with a long shelf life, excellent solder-ability, and an ideal surface for wire bonding.

However, as you may already know, these coatings are relatively expensive options because of the gold, palladium, and nickel involved - so the question we hear is 'what is the best analytical tool for measuring ENIG and ENEPIG coatings?

Read More