Evaluation of test equipment for the detection of contamination on electronic circuits

The reproducibility, sensitivity and ease of operation of test equipment for the detection of ionizable contaminants on the surface of printed circuit assemblies were assessed. The characteristics of the test equipment are described. Soldering fluxes were chosen as contaminants and were applied in controlled amounts to printed-circuit board assemblies possessing two different component populations. Results show that the relationship between equipment readings varies with flux type. Each kind of test equipment gives a good measure of board cleanliness, although reservations exist concerning the interpretation of such results. A test method for the analysis of total (organic and inorganic) halides in solder fluxes is presented.