The Effectiveness of IPA/DI on No-clean Flux Residues

This article studies the ability of the current 75%IPA/25%DI extraction solution, commonly used to detect ion contamination since the 1960s, to detect and quantify new technology weak organic acids common in modern soldering materials employing ROSE, Gravimetric, and Ion Chromatography.

The continuous challenge in the electronics industry is to keep up with the demand for smaller, faster, and more reliable electronics. This places great strains on the manufacturers of those electronics, and those that supply the materials they use.  When ion contamination testing was developed in the mid-20th century, adipic acid was most common in soldering materials and well matched to the 75% IPA/ 25% DI water solution developed to detect residues.  In the ensuing 50 or so years, soldering materials have evolved greatly from fluxes that were all but universally cleaned to fluxes and pastes that for most users are not cleaned. Not surprisingly, that transition included significant changes in flux material ingredients, particularly new materials commonly referred to today as weak organic acids (WOA) rather than adipic acid. This paper will evaluate the solubility, reactivity and detectability of those new materials and contrast them with the original baseline materials from long, long ago employing a range of commonly accepted instruments commonly used for this purpose today.

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