Author: Michael Konrad Company: Aqueous Technologies Date Published: 6/5/2018
ICSR (Soldering and Reliability)
Abstract: Once upon a time we cleaned virtually all circuit assemblies. That was until the discovery that certain Chlorofluorocarbons (CFC's) contributed to the loss of the ozone layer. The industry's most popular cleaning solvents, used to remove flux after soldering, contained CFC's. Eventually (in 1985), an international treaty known as the Montreal Protocol was signed (Figure 1), and our industry witnessed the elimination of many CFC-based cleaning solvents. Necessity being the mother of invention, alternate cleaning materials and methods were introduced. While these alternate materials and methods would prove effective, they paled in comparison to another technology introduced at the same time. This technology promised to eliminate the cleaning process altogether. This was the birth of "no-clean" flux. A flux that left behind very little residue, so little in fact, the assembly would not require cleaning.
It's interesting to note that the Montreal Protocol is one of only two treaties ratified by all United Nations Member Countries.